Needing a wash, being a messy eater? (6)

I believe the answer is:

grubby

I'm a little stuck... Click here to teach me more about this clue!

'eater?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for grubby that I've seen before include "Dirty or unwashed, as urchin may be" , "Soiled" , "Dirty, grimy" , "Dirty, could do with with a wash" , "Squalid" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.