habit has 5 distinct synonyms spread across 4 of its 7 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.
(psychology) an automatic pattern of behavior in reaction to a specific situation; may be inherited or acquired through frequent repetition
“owls have nocturnal habits”
Synonyms, antonyms and the broader and narrower relations for habit come from Princeton University’s WordNet. Full sources and licences.
a distinctive attire worn by a member of a religious order
the general form or mode of growth (especially of a plant or crystal)
“a shrub of spreading habit”
attire that is typically worn by a horseback rider (especially a woman's attire)