O

Oasis An area in a desert where there is water and plants
Oath Formal and serious promises to tell the truth or to do something
Obese Excessively fat – overweight.
Obituary Notice of the death of a person.
Oblation Offering made to God.
Obligatory That which is required by law, rule or custom.
Obliterate Destroy completely remove all traces.
Obloquy Harsh or critical statements about someone
Obscene Very offensive in usually a shocking way
Obscurantist Person who is opposed to eulightment.
Obsequies Funeral rites.
Obsequious Too eager to help or obey someone important
Observatory Building equipped with a powerful telescope for astronomical observations.
Obsidian Dark volcanic.
Obsolescent Passing out of use.
Obsolete Word no longer in use.
or
That which made out of date.
or
No longer used because something newer exists
or
No longer used Or Out of date
Obstetrician Specialist in pregnancy and childbirth.
Obstetrics Branch of medicines dealing with pregnancy.
Obstetrics study of midwifery
Obtuse Slow in understanding.
Obvious That which is clear to eye or mind.
Occupant Person who occupies a house or land, etc.
Oceanography Study of oceans and their phenomena.
or
study of oceans
Ochlocracy government by mobs
Ochlomania An obsession with crowds
Ochlophobia fear of crowds
Ochophobia The fear of vehicles
Octarchy government by eight people
Octogenarian Persons who are between 80 and 89 years old
Odology science of the hypothetical mystical force of God
Odometer Instrument used to measure the distance covered by wheeled vehicles.
Odontograph Teeth.
Odontology study of teeth
Odontomancy divination using teeth
Oenology study of wines
Oenomancy divination by studying appearance of wine
Oenomania obsession or craze for wine
Oenophile one who is fond of or loves wine
Oenophobia fear or hatred of wine
Offender A person who commits a crime
Offshoot Something (such as a business) that develops from something larger
Oikology science of housekeeping
Oikomania An obsession with home
Oinomancy divination using wine
Olfactology study of the sense of smell
Olfactory Of the sense of smell.
Oligarchy State in which the few govern the many.
or
The government by the few
or
Government by divine laws.
or
government by a few
Oligomania obsession with a few thoughts or ideas
Oligopoly State of limited competition, in which a market is shared by a small number of producers or sellers
Ololygmancy fortune-telling by the howling of dogs
Ombrology study of rain
Ombrophilous tolerant of large amounts of rainfall
Ombrophobia fear of rain
Ombudsman Persons (such as a government official or an employee) who investigate complaints and try to deal with problems fairly
Omega The same book or piece of writing as the one that has just been mentioned
Omen Something that is believed to be a sign or warning of something that will happen in the future
Omithophobia fear of birds
Omni form Having every form.
Omnibus Gathering of all things.
Omnifarious Of all sorts.
or
Comprising or relating to all sorts or varieties
Omniform Having every form.
Omnigenous Comprising all kinds.
Omnipotent One who is all powerful.
or
Having “complete or unlimited power
or
All-powerful.
or
Present in all places and at all times.
or
One who is present everywhere
Omnipresent/Ubiquitous Praise too much in order to please. Prayer for the dead.
Omniscient One who is having the knowledge of everything (god).
or
One who knows everything.
or
Knowing everything: having unlimited understanding or knowledge
Omnism A belief in all religions
Omnivore Plant and meat eater – human – bears etc.
Omnivorous One who eats everything.
or
Eating both plants and animals : eager to learn about many different things
or
An animal or a human being that eats any kind of food
or
eating anything; eating both plant and animal matter
Omophagy eating of raw flesh as a ritual observance
Omoplatoscopy divination by observing cracks in burning scapulae
Oncologist Specialist in tumors and cancers.
Oncology study of tumours
Oneirology study of dreams
Oneiromancy divination by dreams
Onerous Difficult and unpleasant to do or deal with
Oniomania mania for making purchases
Onomancy divination using proper names
Onomasiology study of nomenclature
Onomastics study of proper names
Onomatophobia fear of hearing a certain word
Onomatopoeia The formation of a word from a sound associated with what is named
Onslaught Strong or violent attack
Ontology science of pure being; the nature of things
Onychomancy divination by the fingernails
Onychophagist nail-biter
Onychotillomania compulsive picking at the fingernails
Onymancy divination by the fingernails
Oology study of eggs
Oomancy divination using eggs
Opaque through which light cannot pass.
or
not letting light through : not transparent, difficult to understand or explain
or
not allowing light to pass through
or
Incapable of being seen through
Op-ed Pages in newspapers opposite the editorial page that contains comment on the news and articles on particular subjects
Opera Dramatic works in which all or most of the words are sung to music; works of this type as an art form or entertainment
Ophidian About snakes.
Ophidiomancy divination using snakes
Ophidiophobia fear of snakes
Ophiolatry Worship of snakes
Ophiology study of snakes
Ophiomancy divination by watching snakes
Ophiophagous eating snakes
Ophiophilist snake-lover
Ophiophobia Fear of snakes.
Ophthalmologist /Oculist Specialist in the eye disease
Ophthalmology study of eye diseases
Ophthalmophobia fear of being stared at
Opportunist Someone who tries to get an advantage or something valuable from a situation without thinking about what is fair or right
Opprobious Scornful and contemptuous language.
Opprobrious Scornful and contemptuous language.
Opprobrium Disgrace resulting from outrageously, shameful conduct infany.
Opsomania An obsession with a particular food
Opthalmia Inflammation of the eyes.
Optician Some one who tests eyesight and sells glasses.
or
Persons whose job is to sell eyeglasses and contact lenses, to make sure that they fit correctly, and sometimes to make eyeglasses
Optics study of light
Optimism Tendency to look upon the bright side of things.
or
The doctrine the everything in nature is for one’s good.
or
A doctrine that we live in the best of all possible worlds
or
Optimism Feelings or belief that good things will happen in the future
Optimist One who looks at the bright side of things.
Optimize Making (something) as good or as effective as possible
Optology study of sight
Optometry science of examining the eyes
Optophobia fear of opening one’s eyes
Opulent Very comfortable and expensive
Oracy An ability to express one self well in speech
Oraphalomancy divination from the knots in the umbilical cord
Orarium book of private devotions
Orator One who makes an eloquent public speech.
or
Persons who make speeches and are very good at making them
Orbit Curved paths followed by a planet or an object as it moves around another planet, star, moon, etc
Orchard Places where people grow fruit trees
Orchestra Groups of musicians who play usually classical music together and who are led by a conductor
Orchidology study of orchids
Orchidomania abnormal obsession with orchids
Ordeal Severe test of character or endurance.
or
Experiences that are very unpleasant or difficult
Ordinance Laws or regulations made by a government
or
Laws or regulations made by a city, town or the government
Ordnance Military supplies including weapons, ammunition, armor, vehicles, etc.
Oreximania A compulsion to eat
Orgy Something that is done too much and in a wild way
Orient Placing (something) in a particular position or direction
Origami Japanese decorative art of creating shapes by folding paper
or
Japanese art of folding paper into shapes that look like birds, animals, etc.
Ornate Style in which a writer makes a display of his knowledge.
Ornithologist One who specializes in the study of birds.
Ornithology Study of birds.
or
Science of birds.
Ornithomancy divination by observing flight of birds
Orology study of mountains
Orphan Child whose parents are dead
or
Child without father or mother.
or
Charitable home for orphans.
or
Places where children whose parents have died can live and be cared for
Ortheopist One who pronounce too clearly.
Orthodox One who holds established opinion.
or
Confirming to attitudes – Principles that are generally approved.
or
Accepting and closely following the traditional beliefs and customs of a religion
Orthodox One who holds established opinion.
Orthoepy study of correct pronunciation
Orthography Art of correct spelling.
or
study of spelling
Orthopedist Specialist in the disease of bones.
Orthopterology study of cockroaches
Oryctology mineralogy or paleontology
Oryctomancy divination using excavated objects
Oryzivorous rice-eating
Oscillating To make like pendulum (to and fro).
Osculatory carved tablet kissed by priest during celebration of mass
Osmics scientific study of smells
Osmology study of smells and olfactory processes
Osphresiology study of the sense of smell
Ossivorous feeding on bones
Ossomancy divination using bones
Ostensory container for holding consecrated communion wafers
Ostentatious Displaying wealth, knowledge, etc., in a way that is meant to attract attention, admiration, or envy
Osteology Relating to bones.
or
study of bones
Ostomania An abnormal desire to return to familiar places
Ostracism Scarifying for country.
Ostracize Excluding (someone) from a group
Ostreophagous oyster-eating
Otiose Having no useful purpose
Otologist Ear specialist
Otology study of the ear
Otorhinolaryngolog study of ear, nose and throat
Ouine Of or about sheep.
Ouiparcus Producing eggs that mature and hetch outside of the body.
Ouranomancy divination using the heavens
Outbreak Sudden start or increase of fighting or disease
Outburst Sudden expressions of strong feeling, sudden increase in activity
Outcast Someone who is not accepted by other people
Outcaste Persons who are expelled from their caste
Outcry Expressions of strong anger or disapproval by many people
Outdo Doing better than (someone or something): to be more successful than (someone or something)
Outfit All the clothing or articles needed for a purpose.
or
Sets of clothes that are worn together : group of people working together in the same activity
Outing Brief trips that people take for fun usually as a group
Outlaw Persons who have broken the law and who are hiding or running away to avoid punishment
Outlay An amount of money that is spent
Outlet Way out for water or stream.
or
Something that people use to express their emotions or talents
Outline Drawing or pictures that show only the shape of an object
Outlook Way that a person thinks about things
Outnumbered Exceeded in number
Outpost Observation post away from main body of the army.
Outrage Extreme anger : a strong feeling of unhappiness because of something bad, hurtful, or morally wrong
Outrider Someone who goes in advance of an automobile or person to clear a passage.
or
Policeman riding on a motorcycle as a guard to a VIP
Outsmart Defeating or tricking (someone) by being more intelligent or clever
Outsource Sending away (some of a company’s work) to be done by people outside the company
Outspoken Talking in a free and honest way about one’s opinions
Ovation Enthusiastic clapping by an audience as a sign of their approval
Overleaf On the other side of the page of sheet.
Oversight Mistakes made because someone forgets or fails to notice something
Overwrought Very excited or upset
Ovicide Killing the eggs of insects
Oviparous Bearing young by eggs.
Ovivorous eating eggs
Oxymoron A combination of words that have opposite or very different meanings