IN'CUBUS, noun [Latin incubo, to lie on.] 1. The nightmare; an oppression of the breast in sleep, or sense of weight, with an almost total loss of the power of moving the body, while the imagination is frightened or astonished. 2. A demon; an imaginary being or fairy.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI