peril vs imperil

peril is a noun but imperil is not a noun.

Word	Noun	Adjective	Verb	Adverb
peril	Yes	No	Yes	No
imperil	No	No	Yes	No

As verbs, peril and imperil are synonyms defined as:

Other synonyms of peril include endanger, jeopardise, jeopardize, menace, threaten.

peril (noun)	imperil (noun)
a venture undertaken without regard to possible loss or injury
a source of danger; a possibility of incurring loss or misfortune
a state of danger involving risk

peril (verb)	imperil (verb)
put in a dangerous, disadvantageous, or difficult position	pose a threat to; present a danger to
pose a threat to; present a danger to