counteract vs undermine

counteract and undermine both are verbs.

Word	Noun	Adjective	Verb	Adverb
counteract	No	No	Yes	No
undermine	No	No	Yes	No

As verbs, counteract and undermine are synonyms defined as:

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

counteract (verb)	undermine (verb)
act in opposition to	hollow out as if making a cave or opening
destroy property or hinder normal operations	destroy property or hinder normal operations
oppose or check by a counteraction
oppose and mitigate the effects of by contrary actions