Like food that's not clean? (6)
I believe the answer is:
grubby
'like' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'food that's not clean?' is the wordplay.
'food' becomes 'grub' (grub is a kind of food).
'that's not clean?' becomes 'by' (I can't justify this - if you can you should believe this answer much more).
'grub'+'by'='GRUBBY'
Can you help me to learn more?
(Other definitions for grubby that I've seen before include "Dirty, grimy" , "Dirty, could do with with a wash" , "Dirty or unwashed, as urchin may be" , "Covered with ingrained dirt" , "Squalid" .)