incapable
     adj 1: (followed by `of') lacking capacity or ability; "incapable
            of carrying a tune"; "he is incapable of understanding
            the matter"; "incapable of doing the work" [ant: {capable}]
     2: not being susceptible to or admitting of something (usually
        followed by `of'); "incapable of solution" [syn: {incapable(p)}]
     3: lacking the necessary skill or knowledge etc.; "an incapable
        helper" [syn: {unqualified}]
     4: (followed by `of') not having the temperament or inclination
        for; "simply incapable of lying" [ant: {capable}]
     5: not meeting requirements; "unequal to the demands put upon
        him" [syn: {incompetent}, {unequal to(p)}]
Source: WordNet® 2.0