the GNU version of the Collaborative International Dictionary of English
adj. 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.
The Century Dictionary and Cyclopedia
Not able.
Lacking in ability; incapable.
Weak; helpless; useless.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. (usually followed by `to') not having the necessary means or skill or know-how
adj. lacking in power or forcefulness
adj. (usually followed by `to') lacking necessary physical or mental ability