bob has 11 distinct synonyms spread across 7 of its 12 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.
a former monetary unit in Great Britain
a hair style for women and children; a short haircut all around
a hanging weight, especially a metal ball on a string
a short abrupt inclination (as of the head)
“he gave me a short bob of acknowledgement”
move up and down repeatedly
“her rucksack bobbed gently on her back”
Synonyms, antonyms and the broader and narrower relations for bob come from Princeton University’s WordNet. Full sources and licences.
cut hair in the style of a bob
“Bernice bobs her hair these days!”