complication vs complexity

complication and complexity both are nouns.

Word	Noun	Adjective	Verb	Adverb
complication	Yes	No	No	No
complexity	Yes	No	No	No

As nouns, complexity is a hypernym of complication; that is, complexity is a word with a broader meaning than complication:

Other hypernyms of complication include complexness.

complication (noun)	complexity (noun)
the act or process of complicating	the quality of being intricate and compounded
puzzling complexity
a development that complicates a situation
a situation or condition that is complex or confused
any disease or disorder that occurs during the course of (or because of) another disease