Nick not seen at church (5)
I believe the answer is:
notch
'nick' is the definition.
(both can mean a small cut or impression)
'not seen at church' is the wordplay.
'seen at' is a charade indicator (letters next to each other).
'church' becomes 'ch' (common abbreviation).
'not'+'ch'='NOTCH'
(Other definitions for notch that I've seen before include "Salad plant, garnish" , "Nick; small cut" , "Snick" , "Cleft" , "Dent" .)