Faulty, a.
1. Containing faults, blemishes, or defects; imperfect; not fit for the use intended. Created once So goodly and erect, though faulty since. Milton.
2. Guilty of a fault, or of faults; hence, blamable; worthy of censure. Shak. The king doth speak . . . as one which is faulty. 2 Sam. xiv. 13.
Shades of meaning
Fernald lists faulty only as an antonym, under perfect.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given