clutch has 15 distinct synonyms spread across 7 of its 10 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 tense critical situation
“he is a good man in the clutch”
a number of birds hatched at the same time
a collection of things or persons to be handled together
a pedal or lever that engages or disengages a rotating shaft and a driving mechanism
“he smoothely released the clutch with one foot and stepped on the gas with the other”
a coupling that connects or disconnects driving and driven parts of a driving mechanism
“this year's model has an improved clutch”
Synonyms, antonyms and the broader and narrower relations for clutch come from Princeton University’s WordNet. Full sources and licences.
hold firmly, usually with one's hands
“She clutched my arm when she got scared”