insignificant vs unimportant

insignificant and unimportant both are adjectives.

Word	Noun	Adjective	Verb	Adverb
insignificant	No	Yes	No	No
unimportant	No	Yes	No	No

As adjectives, insignificant and unimportant are synonyms defined as:

insignificant (adjective)	unimportant (adjective)
devoid of importance, meaning, or force	not important
signifying nothing	devoid of importance, meaning, or force
of little importance or influence or power; of minor status
small and unimpressive