snake has 7 distinct synonyms spread across 5 of its 9 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.
limbless scaly elongate reptile; some are venomous
a tributary of the Columbia River that rises in Wyoming and flows westward; discovered in 1805 by the Lewis and Clark Expedition
a long faint constellation in the southern hemisphere near the equator stretching between Virgo and Cancer
something long, thin, and flexible that resembles a snake
a long flexible steel coil for dislodging stoppages in curved pipes
move smoothly and sinuously, like a snake
form a snake-like pattern
“The river snakes through the valley”
move along a winding path
“The army snaked through the jungle”
Synonyms, antonyms and the broader and narrower relations for snake come from Princeton University’s WordNet. Full sources and licences.