Synonyms for Sluggish:

adj.

all (adjective)
slow, dull.
dull (adjective)
apathetic, obtuse, doltish, boorish, bovine, blunt, lethargic, besotted, dim, loutish, dense, comatose, ponderous, slow, cloddish, benumbed, thick-witted, stupefied, sleepy, drowsy, dull, soporific.
dull, slow-moving (adjective)
languid, indolent, apathetic, dragging, hebetudinous, sluggard, languorous, torpid, phlegmatic, listless, inactive, off, lifeless, slack, dopey, stagnant, slothful, leaden, down, lumpish, lethargic, inert, slow, comatose.
fatigued (adjective)
exhausted, Wayworn, tired, drowsy, weary, fatigued, worn-out, Frazzled, enervated, sleepy, Flagged, lethargic, run down.
gray (adjective)
leaden.
inert (adjective)
still, languid, passive, static, lifeless, comatose, sedentary, sluggard, stagnant, insensible, idle, apathetic, stationary, inanimate, Reposing, languorous, inert, paralytic, motionless, listless, lethargic, inactive, catatonic, dormant, vegetative, immobile.
lethargic (adjective)
lumpish, leaden, dopey, lackadaisical, slow, lethargic, phlegmatic, listless, dull, unhurried, lazy, benumbed, torpid, insensible, drugged, lifeless, languid, slothful, indolent, apathetic, tired, leisurely, languorous, drooping.
slow (adjective)
dawdling, crawling, plodding, dragging, Loitering, slowpoke, lingering, phlegmatic, leisurely, lethargic, poky, Delaying, slow, Trudging, creeping.
stuporous (adjective)
stuporous.

n.

automatic, auxiliary, clockwork, built, clean, clever, broken, cordless, analog, automatically. down, measured, stately, sedate, slack, soft, off, steady, deliberate, increase. hebetudinous, stuporous, action. industrious, shiftless, sluggard, do-nothing.

Other synonyms:

hebetudinous. stuporous, shiftless, do-nothing. down. off. soft.

Usage examples for sluggish

  1. His body was dull and heavy, sluggish – The Hidden Places by Bertrand W. Sinclair
  2. And she was surprised that his step should sound so sluggish and heavy, accustomed as she was to hear him fill the whole house with the brisk noise of his movements. – The Twilight of the Souls by Louis Couperus
  3. They smoked innumerable cigars and strolled out through the grounds and sat by the river, and threw stones into its sluggish current, waiting while hours went by. – Mr. Achilles by Jennette Lee