coup vs coup d'etat

coup and coup d'etat both are nouns.

Word	Noun	Adjective	Verb	Adverb
coup	Yes	No	No	No
coup d'etat	Yes	No	No	No

As nouns, coup and coup d'etat are synonyms defined as:

coup and coup d'etat: a sudden and decisive change of government illegally or by force

Other synonyms of coup include putsch, takeover.

coup (noun)	coup d'etat (noun)
a sudden and decisive change of government illegally or by force	a sudden and decisive change of government illegally or by force
a brilliant and notable success