[ op-uh-zish-uhn ]
See synonyms for: oppositionoppositional on Thesaurus.com

  1. the action of opposing, resisting, or combating.

  2. antagonism or hostility.

  1. a person or group of people opposing, criticizing, or protesting something, someone, or another group.

  2. Sometimes Opposition . the major political party opposed to the party in power and seeking to replace it.

  3. the act of placing opposite, or the state or position of being placed opposite.

  4. the act of opposing, or the state of being opposed by way of comparison or contrast.

  5. Logic.

    • the relation between two propositions that have the same subject and predicate, but which differ in quantity or quality, or in both.

    • the relation between two propositions in virtue of which the truth or falsity of one of them determines the truth or falsity of the other.

  6. Astronomy. the situation of two heavenly bodies when their longitudes or right ascensions differ by 180°: The moon is in opposition to the sun when the earth is directly between them.

  7. Astrology. the situation of two heavenly bodies or groups of heavenly bodies whose celestial longitudes differ by 180°, conducive to confrontation or revelation: an astrological aspect.

  8. Electricity. the condition that exists when two waves of the same frequency are out of phase by one-half of a period.

  9. Linguistics.

    • the relationship between any two alternative units within a linguistic system, especially between minimally distinct phonemes.

    • the feature that constitutes the difference between two such units.

Origin of opposition

First recorded in 1350–1400; from Latin oppositiōn- (stem of oppositiō ), equivalent to opposit(us) (see opposite) + -iōn- -ion; replacing Middle English opposicioun, from Old French opposicion, from Latin as above

Other words from opposition

  • op·po·si·tion·al, adjective
  • op·po·si·tion·less, adjective
  • non·op·po·si·tion, noun
  • pre·op·po·si·tion, noun
  • su·per·op·po·si·tion, noun

Words that may be confused with opposition

Words Nearby opposition

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use opposition in a sentence

British Dictionary definitions for opposition


/ (ˌɒpəˈzɪʃən) /

  1. the act of opposing or the state of being opposed

  2. hostility, unfriendliness, or antagonism

  1. a person or group antagonistic or opposite in aims to another

    • the opposition a political party or group opposed to the ruling party or government

    • (capital as part of a name, esp in Britain and other Commonwealth countries): Her Majesty's Loyal Opposition

    • in opposition (of a political party) opposing the government

  2. a position facing or opposite another

  3. the act of placing something facing or opposite something else

  4. something that acts as an obstacle to some course or progress

  5. astronomy

    • the position of an outer planet or the moon when it is in line or nearly in line with the earth as seen from the sun and is approximately at its nearest to the earth

    • the position of two celestial bodies when they appear to be diametrically opposite each other on the celestial sphere: Compare conjunction (def. 4)

  6. astrology an exact aspect of 180° between two planets, etc, an orb of 8° being allowed: See conjunction (def. 5), square (def. 10), trine (def. 1)

  7. logic

    • the relation between propositions having the same subject and predicate but differing in quality, quantity, or both, as with all men are wicked; no men are wicked; some men are not wicked

    • square of opposition a diagram representing these relations with the contradictory propositions at diagonally opposite corners

  8. the opposition chess a relative position of the kings in the endgame such that the player who has the move is at a disadvantage: his opponent has the opposition

Derived forms of opposition

  • oppositional, adjective
  • oppositionist, noun
  • oppositionless, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for opposition


[ ŏp′ə-zĭshən ]

  1. A characteristic movement of the primate thumb, in which the pad of the thumb can be placed in contact with the pads of the fingers of the same hand.

  2. The position of two celestial bodies when their celestial longitude differs by 180°, especially a configuration in which Earth lies on a straight line between the Sun and a superior planet or the Moon. Planets in this position rise as the Sun sets and are visible all night long, reaching their highest point in the sky at midnight; the Moon in this position is full. Compare conjunction. See more at elongation.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.