crimson vs redden

crimson is a noun but redden is not a noun.

Word	Noun	Adjective	Verb	Adverb
crimson	Yes	Yes	Yes	No
redden	No	No	Yes	No

As verbs, crimson and redden are synonyms defined as:

Other synonyms of crimson include blush, flush.

crimson (noun)	redden (noun)
a deep and vivid red color

crimson (adjective)	redden (adjective)
characterized by violence or bloodshed
of a color at the end of the color spectrum (next to orange); resembling the color of blood or cherries or tomatoes or rubies
(especially of the face) reddened or suffused with or as if with blood from emotion or exertion

crimson (verb)	redden (verb)
turn red, as if in embarrassment or shame	turn red, as if in embarrassment or shame
	turn red or redder
	make red