fizzle out vs peter out

fizzle out and peter out both are verbs.

Word	Noun	Adjective	Verb	Adverb
fizzle out	No	No	Yes	No
peter out	No	No	Yes	No

As verbs, fizzle out and peter out are synonyms defined as:

Other synonyms of fizzle out include fizzle, taper off.

fizzle out (verb)	peter out (verb)
end weakly	use up all one's strength and energy and stop working
	end weakly