Sort unlikely to appreciate popular grid (7)
I believe the answer is:
ingrate
'sort' is the definition.
(I have seen 'Thankless sort' mean 'ingrate' so perhaps 'sort' could also mean 'ingrate')
'unlikely to appreciate popular grid' is the wordplay.
I cannot quite see how this works, but
'appreciate' could be 'rate' (I've seen this before) and 'rate' is present in the answer.
'popular' could be 'in' ('in' can mean trendy) and 'in' is found within the answer.
A single letter 'g' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ingrate that I've seen before include "Does one not appreciate" , "Thankless sort" , "Unthankful person" , "Ungrateful person" , "Churlish type" .)