strap has 8 distinct synonyms spread across 2 of its 8 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. Its one recorded opposite is unstrap.
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.
an elongated leather strip (or a strip of similar material) for binding things together or holding something in position
hanger consisting of a loop of leather suspended from the ceiling of a bus or train; passengers hold onto it
a band that goes over the shoulder and supports a garment or bag
secure (a sprained joint) with a strap
Synonyms, antonyms and the broader and narrower relations for strap come from Princeton University’s WordNet. Full sources and licences.