imperative vs peremptory

imperative is a noun but peremptory is not a noun.

Word	Noun	Adjective	Verb	Adverb
imperative	Yes	Yes	No	No
peremptory	No	Yes	No	No

imperative (noun)	peremptory (noun)
some duty that is essential and urgent
a verb in the imperative mood.
a mood that expresses an intention to influence the listener's behavior

imperative (adjective)	peremptory (adjective)
requiring attention or action	putting an end to all debate or action
relating to verbs in the imperative mood	offensively self-assured or given to exercising usually unwarranted power
	not allowing contradiction or refusal