cool off vs simmer down

cool off and simmer down both are verbs.

Word	Noun	Adjective	Verb	Adverb
cool off	No	No	Yes	No
simmer down	No	No	Yes	No

As verbs, cool off and simmer down are synonyms defined as:

cool off and simmer down: become quiet or calm, especially after a state of agitation

Other synonyms of cool off include calm, calm down, chill out, cool it, settle down.

cool off (verb)	simmer down (verb)
lose intensity	become quiet or calm, especially after a state of agitation
become quiet or calm, especially after a state of agitation
feel less enamoured of something or somebody