Synonyms and related words :
aberrant, abnormal, amorphous, anomalistic, anomalous, arrested, babbling, backward, blithering, burbling, crackbrained, cracked, crazy, cretinistic, cretinous, deviative, different, dithering, divergent, driveling, drooling, eccentric, erratic, formless, half-baked, half-witted, heteroclite, heteromorphic, idiotic, imbecile, imbecilic, irregular, low, maundering, mentally defective, mentally deficient, mentally handicapped, mentally retarded, mongoloid, moronic, not all there, retarded, shapeless, simple, simpleminded, simpletonian, slobbering, stray, straying, subpar, unnatural, wandering