opposite — situated, placed, or lying face to face with something else or each other, or in corresponding positions with relation to an intervening line, space, or thing: opposite ends of a room.
about-face — An about-face is a complete change of attitude or opinion.
back — If you move back, you move in the opposite direction to the one in which you are facing or in which you were moving before.
bottom — The bottom of something is the lowest or deepest part of it.
contradiction — If you describe an aspect of a situation as a contradiction, you mean that it is completely different from other aspects, and so makes the situation confused or difficult to understand.
contradictory — If two or more facts, ideas, or statements are contradictory, they state or imply that opposite things are true.
converse — If you converse with someone, you talk to them. You can also say that two people converse.
flip-flop — Informal. a sudden or unexpected reversal, as of direction, belief, attitude, or policy.
rear — the back of something, as distinguished from the front: The porch is at the rear of the house.
regression — the act of going back to a previous place or state; return or reversion.
retrogression — the act of retrogressing; movement backward.