- (archaic) soporific, sleep-inducing
1908, Lafcadio Hearn, King Candaules:
- And she poured from a golden urn, into a cup of the same metal, the sombre-coloured beverage which she had mingled with the soporiferous juice of the nepenthe.
1910, Various, International Short Stories= French:
- At last the soporiferous fumes of the wine lulled him into a gentle repose.
1922, Charles Sylvester, Journeys Through Bookland, Vol. 5:
- All this I was told; for, while the whole operation was performing, I lay in a profound sleep, by the force of that soporiferous medicine infused into my liquor.