drab vs dingy

drab is a noun but dingy is not a noun.

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

As adjectives, drab and dingy are synonyms defined as:

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

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

drab (adjective)	dingy (adjective)
of a light brownish green color	causing dejection
lacking brightness or color; dull	thickly covered with ingrained dirt or soot
causing dejection	(of color) discolored by impurities; not bright and clear
lacking in liveliness or charm or surprise