the GNU version of the Collaborative International Dictionary of English
adj. Causing sleep; somniferous; soporific.
The Century Dictionary and Cyclopedia
Causing or tending to cause sleep; soporific.
Sleepy; somnolent.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. inducing mental lethargy
adj. sleep inducing
Word Usage
"The invalid held up, as if in thankfulness, his wasted hands to Heaven, and resisting no longer the soporiferous operation of the elixir, sunk down in a gentle sleep."