hollow out vs undermine

hollow out and undermine both are verbs.

Word	Noun	Adjective	Verb	Adverb
hollow out	No	No	Yes	No
undermine	No	No	Yes	No

As verbs, undermine is a hyponym of hollow out; that is, undermine is a word with a more specific, narrower meaning than hollow out:

Other hyponyms of hollow out include gouge, rout, scallop, scollop, hole, draw in, suck in, scoop out, cavern, cavern out, cave, dig, dig out, excavate, core.

hollow out (verb)	undermine (verb)
remove the interior of	hollow out as if making a cave or opening
	destroy property or hinder normal operations