ability vs acquirement

ability and acquirement both are nouns.

Word	Noun	Adjective	Verb	Adverb
ability	Yes	No	No	No
acquirement	Yes	No	No	No

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

ability: possession of the qualities (especially mental qualities) required to do something or get something done
acquirement: an ability that has been acquired by training

ability (noun)	acquirement (noun)
the quality of being able to perform; a quality that permits or facilitates achievement or accomplishment	an ability that has been acquired by training
possession of the qualities (especially mental qualities) required to do something or get something done