capability vs grasp

capability and grasp both are nouns.

Word	Noun	Adjective	Verb	Adverb
capability	Yes	No	No	No
grasp	Yes	No	Yes	No

As nouns, grasp is a hyponym of capability; that is, grasp is a word with a more specific, narrower meaning than capability:

Other hyponyms of capability include perfectibility, compass, range, reach, imperfectibility.

capability (noun)	grasp (noun)
the quality of being capable -- physically or intellectually or legally	the act of grasping
an aptitude that may be developed	an intellectual hold or understanding
the susceptibility of something to a particular treatment	understanding of the nature or meaning or quality or magnitude of something
	the limit of capability

capability (verb)	grasp (verb)
	get the meaning of something
	hold firmly