crawl has 9 distinct synonyms spread across 4 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. 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.
feel as if crawling with insects
“My skin crawled--I was terrified”
be full of
“The old cheese was crawling with maggots”
swim by doing the crawl
“European children learn the breast stroke; they often don't know how to crawl”
a very slow movement
“the traffic advanced at a crawl”
a swimming stroke; arms are moved alternately overhead accompanied by a flutter kick
Synonyms, antonyms and the broader and narrower relations for crawl come from Princeton University’s WordNet. Full sources and licences.
a slow mode of locomotion on hands and knees or dragging the body
“a crawl was all that the injured man could manage”