repercussion vs backlash

repercussion and backlash both are nouns.

Word	Noun	Adjective	Verb	Adverb
repercussion	Yes	No	No	No
backlash	Yes	No	Yes	No

As nouns, repercussion and backlash are synonyms defined as:

Other synonyms of repercussion include rebound, recoil.

repercussion (noun)	backlash (noun)
a movement back from an impact	an adverse reaction to some political or social occurrence
a remote or indirect consequence of some action	a movement back from an impact

repercussion (verb)	backlash (verb)
	come back to the originator of an action with an undesired effect