sear vs blacken

sear is an adjective but blacken is not an adjective.

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

As verbs, sear and blacken are synonyms defined as:

Other synonyms of sear include char, scorch.

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

sear (verb)	blacken (verb)
make very hot and dry	make or become black
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