unable
adjective
(usually followed by `to') not having the necessary means or skill or know-how
“unable to get to town without a car”
“unable to obtain funds”
Oppositesable(usually followed by `to') lacking necessary physical or mental ability
“dyslexics are unable to learn to read adequately”
“the sun was unable to melt enough snow”
lacking in power or forcefulness
“an ineffectual ruler”
“like an unable phoenix in hot ashes”
Source: WordNet 3.1, Princeton University
