pistol-whip vs beat up

pistol-whip and beat up both are verbs.

Word	Noun	Adjective	Verb	Adverb
pistol-whip	No	No	Yes	No
beat up	No	No	Yes	No

As verbs, beat up is a hypernym of pistol-whip; that is, beat up is a word with a broader meaning than pistol-whip:

pistol-whip: beat with a pistol
beat up: give a beating to; subject to a beating, either as a punishment or as an act of aggression

Other hypernyms of pistol-whip include beat, work over.

pistol-whip (verb)	beat up (verb)
beat with a pistol	gather
	give a beating to; subject to a beating, either as a punishment or as an act of aggression