the quality of being able to perform; a quality that permits or facilitates achievement or accomplishment
is a type of (narrower)
an essential and distinguishing attribute of something or someone
"the quality of mercy is not strained"--Shakespeare
is an attribute of
(usually followed by `to') having the necessary means or skill or know-how or authority to do something
"able to swim"; "she was able to program her computer"; "we were at last able to buy a car"; "able to get a grant for the project"
is an attribute of
(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"