countermine vs weaken

countermine is a noun but weaken is not a noun.

Word	Noun	Adjective	Verb	Adverb
countermine	Yes	No	Yes	No
weaken	No	No	Yes	No

As verbs, countermine and weaken are synonyms defined as:

Other synonyms of countermine include counteract, sabotage, subvert, undermine.

countermine (noun)	weaken (noun)
(military) a tunnel dug to defeat similar activities by the enemy

countermine (verb)	weaken (verb)
destroy enemy mines with one's own mines	become weaker
destroy property or hinder normal operations	lessen the strength of
	reduce the level or intensity or size or scope of
	lessen in force or effect
	destroy property or hinder normal operations