no can do

helpless impotent inadequate incapable not able powerless sidelined unfit weak

can't cut it can't hack it can't make the grade clumsy hog-tied impuissant incapacitated incompetent ineffectual inefficacious inefficient inept inoperative no good not cut out for not equal to not up to out of commission unfitted unqualified unskilled

able capable competent fit potent qualified strong sufficient

adequate skillful talented