gloomy vs drab

gloomy is not a noun while drab is a noun.

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

As adjectives, gloomy and drab are synonyms defined as:

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

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

gloomy (adjective)	drab (adjective)
depressingly dark	of a light brownish green color
filled with melancholy and despondency	lacking brightness or color; dull
causing dejection	causing dejection
	lacking in liveliness or charm or surprise