impotent -
lacking power or ability; "Technology without morality is barbarous; morality without technology is impotent"- Freeman J.Dyson; "felt impotent rage"
potent,
stiff,
strong having a strong physiological or chemical effect; "a potent toxin"; "potent liquor"; "a potent cup of tea", "a stiff drink"
infertile,
unfertile,
sterile deficient in originality or creativity; lacking powers of invention; "a sterile ideology lacking in originality"; "unimaginative development of a musical theme"; "uninspired writing"