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; as, unable for work; unable to bear fatigue.
My mother said I must always be intolerant of ignorance but understanding of illiteracy. That some people, unable to go to school, were more educated and more intelligent than college professors. Maya Angelou
I think that humans have a huge capacity to carry pain and sadness. There are things that haunt us our entire lives; we are unable to let them go. The good times seem almost effervescent and dreamlike in comparison with the times that didn't go so well. Henry Rollins
Men ought either to be indulged or utterly destroyed, for if you merely offend them they take vengeance, but if you injure them greatly they are unable to retaliate, so that the injury done to a man ought to be such that vengeance cannot be feared. Niccolo Machiavelli