Medicine/Medical . having the quality of depressing or lowering the vital activities; sedative.

causing a lowering in spirits; dejecting.

causing a drop in value; economically depressing.

Medicine/Medical . a sedative. Compare stimulant ( def. 1 ) .

Chemistry . any agent capable of diminishing a specific property of a substance.

noun

calmant , downer , intoxicant , relaxant , tranquilizer