Appetiser is more pungent after seconds (7)
I believe the answer is:
starter
'appetiser' is the definition.
(I've seen this before)
'more pungent after seconds' is the wordplay.
I cannot really understand how this works, but
'pungent' could be 'tart' (I've seen this in another clue) and 'tart' is present in the answer.
'seconds' could be 's' (abbreviation) and 's' is found within the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'is' is the link.
Can you help me to learn more?
(Other definitions for starter that I've seen before include "First course of meal" , "First course for beginner" , "Beginner, or opening course of meal" , "Hors d'oeuvre" , "Type of home" .)