Like food perhaps that's unhygienic (6)
I believe the answer is:
grubby
'unhygienic' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
'like food perhaps' is the wordplay.
I cannot really understand how this works, but
'like' could be 'y' (similar in meaning) and 'y' is located in the answer.
'food' could be 'b' (B is an example) and 'b' is found within the answer.
The remaining letters 'grub' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'that's' is the link.
Can you help me to learn more?
(Other definitions for grubby that I've seen before include "Squalid" , "Dirty, grimy" , "Soiled" , "Dirty or unwashed, as urchin may be" , "Covered with ingrained dirt" .)