incessantly vs perpetually

incessantly and perpetually both are adverbs.

Word	Noun	Adjective	Verb	Adverb
incessantly	No	No	No	Yes
perpetually	No	No	No	Yes

As adverbs, incessantly and perpetually are synonyms defined as:

Other synonyms of incessantly include always, constantly, forever.

incessantly (adverb)	perpetually (adverb)
invariably	invariably
with unflagging resolve	everlastingly; for all time