somnolent

somnolent \SOM-nuh-luhnt\, adjective:

1. Sleepy; drowsy; inclined to sleep.
2. Tending to cause sleepiness or drowsiness.

In his case, restrained ultimately meant boring, as the audience was lulled into a somnolent state.
-- Teresa Wiltz, "The Hip, the Flip, the Flop", Washington Post, March 3, 2000

Meanwhile, many a somnolent local authority has been stirred into action by Davidson's blunt approach.
-- John Lucas, "Memorials are made of these on the eve of Remembrance Sunday", Daily Telegraph, November 7, 1998

Back in the somnolent heat of Bangalore he wrote a revealing novel entitled Savrola.
-- David Stafford, Churchill and Secret Service

Somnolent is from Latin somnolentus, from somnus, "sleep." A related word is insomnia (in-, "not" + somnus).