RichThesaurus
somnifacient
vs
somnorific
somnifacient
adj
Inducing or causing sleep.
noun
Any pharmaceutical product that causes sleep.
somnorific
adj
soporific; inducing sleep
How often have the words
somnifacient
and
somnorific
occurred in a corpus of books?
(source:
Google Ngram Viewer
)