at rest vs at peace

at rest and at peace both are adjectives.

Word	Noun	Adjective	Verb	Adverb
at rest	No	Yes	No	No
at peace	No	Yes	No	No

As adjectives, at rest and at peace are synonyms defined as:

Other synonyms of at rest include asleep, deceased, departed, gone.

at rest (adjective)	at peace (adjective)
in a state of repose or especially sleep	dead
dead