Drowsy, a. [Compar. Drowsier; superl. Drowsiest.]
1. Inclined to drowse; heavy with sleepiness; lethargic; dozy. "When I am drowsy." Shak. Dapples the drowsy east with spots of gray. Shak. To our age's drowsy blood Still shouts the inspiring sea. Lowell.
2. Disposing to sleep; lulling; soporific. The drowsy hours, dispensers of all good. Tennyson.
3. Dull; stupid. " Drowsy reasoning." Atterbury.
Syn. -- Sleepy; lethargic; dozy; somnolent; comatose; dull heavy; stupid.
Shades of meaning
Fernald has no entry of its own for drowsy; he lists it under slow.
He lists it without comment; the entries above explain its neighbors.