assault has 14 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.
close fighting during the culmination of a military attack
a threatened or attempted physical attack by someone who appears to be able to cause bodily harm if not stopped
thoroughbred that won the triple crown in 1946
the crime of forcing a person to submit to sexual intercourse against his or her will
Synonyms, antonyms and the broader and narrower relations for assault come from Princeton University’s WordNet. Full sources and licences.