depressing vs drab

depressing is not a noun while drab is a noun.

Word	Noun	Adjective	Verb	Adverb
depressing	No	Yes	No	No
drab	Yes	Yes	No	No

depressing (noun)	drab (noun)
	a dull greyish to yellowish or light olive brown

depressing (adjective)	drab (adjective)
causing sad feelings of gloom and inadequacy	of a light brownish green color
	lacking brightness or color; dull
	causing dejection
	lacking in liveliness or charm or surprise