(mathematics) reciprocal

(ACG) reverse harem, a situation in which one woman keeps multiple male lovers

revolt, rebellion / treason

to revolt, to rebel

rape of a male by a female; reverse rape

(slang) closing a flip phone in the wrong direction (and thus breaking it)

(grammar) adversative, contrastive; a particle or conjunction that joins two phrases and indicates that their meanings contrast or differ from one another or from expectation

high treason

in reverse order, opposite sequence, inverse / contrary to reason

the situation reverses itself; the tables are turned; the shoe is on the other foot