succubus

noun

A female demon supposed to descend upon and have sexual intercourse with a man while he sleeps.

An evil spirit; a demon.

A demon fabled to have sexual intercourse with human beings in their sleep.

A demon or fiend; especially, a lascivious spirit supposed to have sexual intercourse with the men by night; a succuba. Cf. incubus.

The nightmare. See Nightmare, 2.