incubus

in·cu·bus

(in'kū-bŭs),

Originally, an evil spirit that would lie on and oppress sleeping people; especially, a male spirit that copulated with sleeping women. Compare: succubus.

[L. fr. incubo, to lie on]

incubus

(1) An evil (male) spirit that copulates with sleeping women. 
(2) An erotic nightmare occurring in a sexually repressed female.

in·cu·bus

(in'kyū-bŭs)

1. Originally, an evil spirit that lay on and oppressed sleeping people, especially, a male spirit that copulated with sleeping women.
Compare: succubus

2. Synonym(s): nightmare.

[L. fr. incubo, to lie on]

incubus

(ĭn′kū-bŭs) [L. incubare, to lie upon]

A nightmare.