Inducing or tending to induce sleep; soporific.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "soporiferous" in a sentence
"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."
"Into this cavern the sun never enters, and a perpetual stillness reigns, no noise being heard but the soft murmur caused by a stream of the river Lethe, which creeps over the pebbles, and invites to slumber; at its entrance grow poppies, and other soporiferous herbs."
"All this I was told; for, while the whole operation was performing, I lay in a profound sleep, by the force of that soporiferous medicine infused into my liquor."