grip has 20 distinct synonyms spread across 8 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 portable rectangular container for carrying clothes
“he carried his small bag onto the plane with him”
the friction between a body and the surface on which it moves (as between an automobile tire and the road)
worker who moves the camera around while a film or television show is being made
to grip or seize, as in a wrestling match
“the two men grappled with each other for several minutes”
Synonyms, antonyms and the broader and narrower relations for grip come from Princeton University’s WordNet. Full sources and licences.