"driving away or preventing sleep," 1721; see somni- + -fuge + -ous.
Entries linking to somnifugous
somni-
before vowels somn-, word-forming element meaning "sleep," from combining form of Latin somnus "sleep, slumber," from PIE root *swep- "to sleep."
-fuge
word-forming element meaning "that which drives away or out," from Modern Latin -fugus, with sense from Latin fugare "to put to flight" (see febrifuge) but form from Latin fugere "to flee" (see fugitive (adj.)).
-ous
word-forming element making adjectives from nouns, meaning "having, full of, having to do with, doing, inclined to," from Old French -ous, -eux, from Latin -osus (compare -ose (1)). In chemistry, "having a lower valence than forms expressed in -ic."