Charybdis One of the hazards Odysseus had to sail past. The other was Scylla.
5L < Gr6 old name of a whirlpool off the NE coast of Sicily, in the Strait of Messina (now called Galofalo): see SCYLLA

Scylla
5L < Gr Skylla6 a dangerous rock on the Italian side of the Straits of Messina, opposite the whirlpool Charybdis: in classical mythology both Scylla and Charybdis were personified as female monsters
between Scylla and Charybdis between two perils or evils, neither of which can be evaded without risking the other