sidekick vs crony

sidekick and crony both are nouns.

Word	Noun	Adjective	Verb	Adverb
sidekick	Yes	No	No	No
crony	Yes	No	No	No

As nouns, sidekick and crony are synonyms defined as:

sidekick and crony: a close friend who accompanies his buddies in their activities

Other synonyms of sidekick include brother, buddy, chum, pal.

sidekick (noun)	crony (noun)
a close friend who accompanies his buddies in their activities	a close friend who accompanies his buddies in their activities