A Drab

1. A fabric, usually of thick cotton or wool, having a dull brownish yellow, dull grey, or dun colour. Synonym: drabcloth
2. The colour of this fabric.

drab:

3. Often in the plural form drabs: apparel, especially trousers, made from this fabric. Drab (color) - Wikipedia
4. (by extension) A dull or uninteresting appearance or situation, unremarkable.