pocket has 7 distinct synonyms spread across 5 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.
a small pouch inside a garment for carrying small articles
Synonyms, antonyms and the broader and narrower relations for pocket come from Princeton University’s WordNet. Full sources and licences.
a supply of money
“they dipped into the taxpayers' pockets”
(bowling) the space between the headpin and the pins behind it on the right or left
“the ball hit the pocket and gave him a perfect strike”
a local region of low pressure or descending air that causes a plane to lose height suddenly
a small isolated group of people
“they were concentrated in pockets inside the city”
an opening at the corner or on the side of a billiard table into which billiard balls are struck