Spot a mole at mid-September? (4)
I believe the answer is:
espy
'spot' is the definition.
(I know that spot can be written as espy)
'a mole at mid-september?' is the wordplay.
'a mole' becomes 'spy' (I've seen this in another clue).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'mid' indicates the central letters.
'september?' becomes 'sep' (short for September).
The central letter of 'sep' is 'e'.
'spy' after 'e' is 'ESPY'.
(Other definitions for espy that I've seen before include "Spot at a distance" , "Spot, notice" , "Observe, notice" , "Watch" , "Pick out at a distance" .)