From Longman Dictionary of Contemporary Englishsoporificsop‧o‧rif‧ic /ˌsɒpəˈrɪfɪk◂ $ ˌsɑː-/ adjective formal SLEEPmaking you feel ready to sleep His voice had an almost soporific effect.
Examples from the Corpus
soporific• In summer, that gushing sound would be refreshingly cool and delightfully soporific.• Kyphi was always burnt after sunset for its effects were soporific and intoxicating.• With his shaved head and soporific disposition, Weller comes across as a kind of Kung Futon.• Cantor had underestimated the soporific effect of the six-course dinner, the two wines and the glass of port.• At the start, everyone was respectful towards him, listening carefully to his soporific explanations.• A libel trial is in large parts intensely soporific, if you are not on the receiving end.• Booze was soporific, the brain was programmed to zero, it curled up and slept.Origin soporific (1600-1700) French soporifique, from Latin sopor “deep sleep” 