Charybdis

(n.) A dangerous whirlpool on the coast of Sicily opposite Scylla on the Italian coast. It is personified as a female monster. See Scylla.

Thesaurus Entries

Charybdis, Maelstrom, back stream, backwash, backwater, countercurrent, counterflow, counterflux, eddy, gulf, gurge, maelstrom, refluence, reflux, regurgitation, swirl, twirl, vortex, whirl, whirlpool