complex vs knotty

complex is a noun but knotty is not a noun.

Word	Noun	Adjective	Verb	Adverb
complex	Yes	Yes	No	No
knotty	No	Yes	No	No

complex (noun)	knotty (noun)
a whole structure (as a building) made up of interconnected or related structures
a conceptual whole made up of complicated and related parts
(psychoanalysis) a combination of emotions and impulses that have been rejected from awareness but still influence a person's behavior
a compound described in terms of the central atom to which other atoms are bound or coordinated

complex (adjective)	knotty (adjective)
complicated in structure; consisting of interconnected parts	highly complex or intricate and occasionally devious
difficult to analyze or understand	used of old persons or old trees; covered with knobs or knots
	making great mental demands; hard to comprehend or solve or believe
	tangled in knots or snarls