incline has 9 distinct synonyms spread across 5 of its 8 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.
bend or turn (one's ear) towards a speaker in order to listen well
“He inclined his ear to the wise old man”
lower or bend (the head or upper body), as in a nod or bow
“She inclined her head to the student”
feel favorably disposed or willing
“She inclines to the view that people should be allowed to expres their religious beliefs”
make receptive or willing towards an action or attitude or belief
“Their language inclines us to believe them”
an elevated geological formation
“he climbed the steep slope”
Synonyms, antonyms and the broader and narrower relations for incline come from Princeton University’s WordNet. Full sources and licences.