Soporous

Part of speech: adjective

Definitions

1. Inducing or characterized by deep sleep or lethargy; tending to cause drowsiness or a state of unconsciousness
2. Causing or associated with a state of profound sleep or sluggishness
3. Bringing on a state of heavy sleep or extreme drowsiness

Etymology: "Sopor" was the Latin word for a deep, heavy sleep, and the Latin adjective "soporus" meant sleep-inducing. English took that adjective and kept it, so "soporous" carries its original sense: causing deep sleep. The ending "-ous" simply means "full of" or "having the quality of," so the word is built from the idea of sleep plus that quality. Its better-known relative is "soporific," which comes from the Latin "soporifer," combining "sopor" with "-fer," meaning "bringing" or "bearing." Both words describe the same effect, but "soporific" became the everyday choice, while "soporous" stayed a rarer alternative.

Synonyms: porous, permeable

Antonyms: impermeable, solid