Definitions for "Drowsy"
Inclined to drowse; heavy with sleepiness; lethargic; dozy.
Disposing to sleep; lulling; soporific.
The etymological notion underlying drowsy seems to be "heaviness," as in eyelids made heavy by dreary, drizzly weather. See: TIRED.
Keywords:  stupid, dull
Dull; stupid.
showing lack of attention or boredom; "the yawning congregation"