peter out vs taper off

peter out and taper off both are verbs.

Word	Noun	Adjective	Verb	Adverb
peter out	No	No	Yes	No
taper off	No	No	Yes	No

As verbs, peter out and taper off are synonyms defined as:

Other synonyms of peter out include fizzle, fizzle out.

peter out (verb)	taper off (verb)
use up all one's strength and energy and stop working	become smaller or less active
end weakly	end weakly