Synonyms for Imperfect:

adj.

blemished (adjective)
marred, flawed, tainted, slit, defective, impure, fractured, discolored, damaged, Scuffed, scarred, deformed, abraded, splotched, stained, specked, Hacked, scraped, spotted, blotched, cracked, disfigured, notched, gashed, flecked, blemished, Nicked, Scored, Scabbed, freckled, tarnished, scratched, distorted, chipped, marked, blistered, defaced, pockmarked, spoiled.
deficient (adjective)
deficient, inadequate, lacking, insufficient.
flawed (adjective)
disfigured, broken, limited, deficient, damaged, defective, marred, faulty, incomplete.
imperfect (adjective)
inadequate, blemished, deficient, defective, tainted, flawed, incomplete, spoiled, blotched, second-rate, faulty.
impure (adjective)
sordid, dirty, defective, slovenly, immoral, obscene, impure, unclean, blemished.
incomplete (adjective)
incomplete.
insufficient (adjective)
insufficient.

n.

future, active, intransitive, finite, causative, continuous, ergative, imperative, impersonal. limited, suboptimal, substandard, undistinguished, disappointing, average, poor, inferior, better, unsatisfactory. imperfect (noun)
flawed, frail, imperfect tense, faulty, progressive, fallible, progressive tense, weak, human, broken, continuous tense, blemished, defective, corrupt, corrupted.

Other synonyms:

continuous, ergative, intransitive, future, impersonal, imperative, causative, finite. poor. active. Other relevant words:
limited, fallible, imperfect tense, ergative, weak, poor, disappointing, impersonal, progressive tense, unsatisfactory, inferior, causative, continuous tense, progressive, broken, finite, intransitive, corrupt, future, corrupted, substandard, human, frail.

Usage examples for imperfect

  1. It was another of those wretched problems offered by this imperfect world for which there seems no remedy. – His Sombre Rivals by E. P. Roe
  2. It is incident to our imperfect nature. – State of the Union Addresses of Thomas Jefferson by Thomas Jefferson
  3. I retain a confused, imperfect recollection of a light streaming upon broken water- of a hard struggle in a deep ford- and of at length sharing in the repose and safety of a cottage, solitary and humble almost as my own. – Leading Articles on Various Subjects by Hugh Miller