hump has 28 distinct synonyms spread across 3 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
round one's back by bending forward and drawing the shoulders forward
have sexual intercourse with
“This student sleeps with everyone in her dorm”
something that bulges out or is protuberant or projects from its surroundings
“the gun in his pocket made an obvious bulge”
Synonyms, antonyms and the broader and narrower relations for hump come from Princeton University’s WordNet. Full sources and licences.