drab vs dismal

drab is a noun but dismal is not a noun.

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

As adjectives, drab and dismal are synonyms defined as:

Other synonyms of drab include blue, dark, dingy, disconsolate, drear, dreary, gloomy, grim, sorry.

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

drab (adjective)	dismal (adjective)
of a light brownish green color	causing dejection
lacking brightness or color; dull
causing dejection
lacking in liveliness or charm or surprise