incubus

Meaning

Noun

• An evil spirit supposed to oppress people while asleep, especially to have sex with women as they sleep.
• A feeling of oppression during sleep, sleep paralysis; night terrors, a nightmare.
• Any oppressive thing or person; a burden.
• One of various of parasitic insects, especially subfamily Aphidiinae (subfamily).

Origin

• From Late Latin incubus, from Latin incubō ("nightmare, one who lies down on the sleeper"), from incubāre, from in- + cubāre.