unable

Synonyms: can’t cut it can’t hack it can’t make the grade clumsy helpless hog-tied impotent impuissant inadequate incapable incapacitated incompetent ineffectual inefficacious inefficient inept inoperative no can do no good not able not cut out for not equal to not up to out of commission powerless sidelined unfit unfitted unqualified unskilled weak

Antonyms: able adequate capable competent fit qualified skillful talented