Synonyms and related words :
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