partner in crime vs henchman

partner in crime and henchman both are nouns.

Word	Noun	Adjective	Verb	Adverb
partner in crime	Yes	No	No	No
henchman	Yes	No	No	No

As nouns, partner in crime and henchman are synonyms defined as:

Other synonyms of partner in crime include collaborator, confederate.

partner in crime (noun)	henchman (noun)
someone who assists in a plot	someone who assists in a plot