feeble

Synonyms: aged ailing chicken debilitated decrepit delicate doddering dopey effete emasculated enervated enfeebled etiolated exhausted failing faint flabby flat fragile frail gentle helpless impotent inadequate incompetent indecisive ineffectual inefficient infirm insubstantial insufficient lame languid low out of gas paltry poor powerless puny sapless sickly slight strengthless tame thin unconvincing vitiated weak weakened weakly wimpy woozy zero

Antonyms: able effective hardy healthy hearty powerful solid sound strong