a bit previous adolescent advanced amateur amateurish arrested at half cock babbling backward blithering burbling callow crackbrained cracked crazy cretinistic cretinous dabbling dilettante dilettantish dithering driveling drooling far ahead fledgling forward green half-assed half-cocked half-grown half-witted hasty idiotic ill-considered ill-digested imbecile imbecilic immature impubic impulsive juvenile maundering mentally defective mentally deficient mentally handicapped mentally retarded mongoloid moronic not all there not firm overhasty oversoon precipitate precocious premature previous raw retarded rushed sciolistic shallow simple simpleminded simpletonian slobbering smattering sophomoric subnormal superficial too early too soon uncrystallized underripe unfledged ungrown unjelled unmatured unmeditated unmellowed unpremeditated unprepared unripe unseasoned untimely