whistle has 4 distinct synonyms spread across 4 of its 11 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.
Synonyms, antonyms and the broader and narrower relations for whistle come from Princeton University’s WordNet. Full sources and licences.
“She whistled a melody”
move, send, or bring as if by whistling
“Her optimism whistled away these worries”
give a signal by whistling
“She whistled for her maid”
a small wind instrument that produces a whistling sound by blowing into it
acoustic device that forces air or steam against an edge or into a cavity and so produces a loud shrill sound