blacken vs sear

blacken is not an adjective while sear is an adjective.

Word	Noun	Adjective	Verb	Adverb
blacken	No	No	Yes	No
sear	No	Yes	Yes	No

As verbs, blacken and sear are synonyms defined as:

Other synonyms of blacken include char, scorch.

blacken (adjective)	sear (adjective)
	(used especially of vegetation) having lost all moisture

blacken (verb)	sear (verb)
make or become black	make very hot and dry
burn slightly and superficially so as to affect color	burn slightly and superficially so as to affect color
	cause to wither or parch from exposure to heat
	become superficially burned