adj. 25B6; adjective
a defective seat belt : FAULTY, flawed, imperfect, shoddy, inoperative, malfunctioning, out of order, unsound; in disrepair, broken; informal on the blink; Brit. informal knackered, duff.
these methods are defective : LACKING, wanting, deficient, inadequate, insufficient.
(dated) a mentally defective child : IMPAIRED, slow, simple, backward, retarded; dated deficient, subnormal, educationally subnormal, ESN.
perfect.