The Oxford Thesaurus An A-Z Dictionary of Synonyms - impotentadj.

1) weak, powerless, helpless, frail, feeble, enervated, debilitated, infirm: When it came to political influence, I was impotent. 2) inadequate, ineffective, ineffectual, inept, incompetent: The attempted robbery was a half-hearted, impotent effort. 3) sterile, barren, infertile, infecund: They never had any children because Dixon was impotent.