(a.) Not able; not having sufficient strength, means, knowledge, skill, or the like; impotent' weak; helpless; incapable; -- now usually followed by an infinitive or an adverbial phrase; as, unable for work; unable to bear fatigue.

ill-qualified impotent inadequate incapable incapable of incompetent ineffective ineffectual inefficient inept inferior maladjusted not equal to not up to powerless unable to unadapted unadjusted unendowed unequipped unfit unfitted ungifted unqualified untalented