abuse vs low blow

abuse and low blow both are nouns.

Word	Noun	Adjective	Verb	Adverb
abuse	Yes	No	Yes	No
low blow	Yes	No	No	No

As nouns, low blow is a hyponym of abuse; that is, low blow is a word with a more specific, narrower meaning than abuse:

Other hyponyms of abuse include billingsgate, scurrility, cut, stinger, invective, vitriol, vituperation.

abuse (noun)	low blow (noun)
improper or excessive use	unscrupulous abuse
cruel or inhumane treatment
a rude expression intended to offend or hurt

abuse (verb)	low blow (verb)
change the inherent purpose or function of something
use wrongly or improperly or excessively
use foul or abusive language towards
treat badly