throttle has 14 distinct synonyms spread across 5 of its 5 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.
kill by squeezing the throat of so as to cut off the air
“he tried to strangulate his opponent”
a valve that regulates the supply of fuel to the engine
a pedal that controls the throttle valve
“he stepped on the gas”
Synonyms, antonyms and the broader and narrower relations for throttle come from Princeton University’s WordNet. Full sources and licences.