soporific
1. so.po.rif.ic \-'rif-ik\ aj [prob. fr. F soporifique, fr. L sopor deep sleep; akin to L somn]us sleep - more at SOMNOLENT 1a: causing or tending to cause sleep 1b: tending to dull awareness or alertness 2: of, relating to, or characterized by sleepiness or lethargy 2. soporific n : a soporific agent; specif : HYPNOTIC