(a.) Destitute of power, force, or energy; weak; impotent\; not able to produce any effect.

anemic asthenic bloodless chicken cowardly crippled debilitated decrepit disabled drooping droopy dull effete etiolated faint faintish featherweight feeble flabby flaccid floppy forceless gone gutless helpless imbecile impotent inactive incapable incapacitated incompetent ineffective ineffectual inefficacious inert infirm languid languorous lightweight limber limp listless lustless marrowless nerveless no-account of no account passive pithless pooped rubbery sapless sinewless slack soft spineless strengthless supine unable unauthoritative unfit unhardened unnerved unstrung weak weakly without any weight