1. The act of opposing; an attempt to check, restrain, or defeat; resistance. The counterpoise of so great an opposition. (Shak) Virtue which breaks through all opposition. (milton)
2. The state of being placed over against; situation so as to front something else.
3. Repugnance; contrariety of sentiment, interest, or purpose; antipathy.
4. That which opposes; an obstacle; specifically, the aggregate of persons or things opposing; hence, in politics and parliamentary practice, the party opposed to the party in power.
5. (Science: astronomy) The situation of a heavenly body with respect to another when in the part of the heavens directly opposite to it; especially, the position of a planet or satellite when its longitude differs from that of the sun 180 deg; signified by the symbol; as, <Jupiter/ <Sun/, opposition of jupiter to the sun.
6. (Science: logic) The relation between two propositions when, having the same subject and predicate, they differ in quantity, or in quality, or in both; or between two propositions which have the same matter but a different form.
Origin: F, fr. L. Oppositio. See Opposite.