adjective.
Lacking the necessary power, authority, or means; not able; incapable.
adjective.
Lacking mental or physical capability or efficiency; incompetent.
adjective.
Not susceptible to action or treatment.
The Century Dictionary and Cyclopedia
Not able.
Lacking in ability; incapable.
Weak; helpless; useless.
the GNU version of the Collaborative International Dictionary of English
adjective.
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.