What is the Latin word for soporific?

The usual Latin words for “soporific” are somnifer, somnificus, sopor; also pōtō. The right choice depends on the sense; see the distinctions below.

English → Latin

“soporific” in Latin

somnifersomniferous somnificusinducing sleep sopora deep sleep, sopor; sleep (in general), slumber; catalepsy; the sleep of death; death; stupefaction; lethargy, stupor; pōtōto drink

The English word soporific itself goes back to Latin sopor.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

soporific

somnifer (Plin., Ov.): somnificus (Plin.): *medicamentum somnum concitans: A soporific (medicine), sopor (Nep., Sen.: ☞ medicamentum somnificum is not classical; potio somnifica is altogether without authority): to administer a soporific, alicui soporem dare: to take a soporific, soporem sumere (Sen., Ep., 83, fin.) or potare.

Quick answer

What is the Latin word for soporific?: The usual Latin words for “soporific” are somnifer, somnificus, sopor; also pōtō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.