significance vs importance

significance and importance both are nouns.

Word	Noun	Adjective	Verb	Adverb
significance	Yes	No	No	No
importance	Yes	No	No	No

As nouns, importance is a hypernym of significance; that is, importance is a word with a broader meaning than significance:

significance (noun)	importance (noun)
the quality of being significant	the quality of being important and worthy of note
a meaning that is not expressly stated but can be inferred	a prominent status
the message that is intended or expressed or signified