Pundit’s first with answer describing police car (5)
I believe the answer is:
panda
'police car' is the definition.
(I've seen this before)
'pundit's first with answer' is the wordplay.
'pundit's first' becomes 'p' (1st letter of 'pundit').
'with' becomes 'and'.
'answer' becomes 'a' (abbreviation eg in Q and A).
'p'+'and'+'a'='PANDA'
'describing' acts as a link.
(Other definitions for panda that I've seen before include "Bamboo-eater" , "Bamboo-eating creature" , "Chinese native" , "Large black-and-white herbivorous mammal" , "Endangered creature" .)