Initially politician easily wins seat (3)
I believe the answer is:
pew
'seat' is the definition.
(pew is a kind of seat)
'initially politician easily wins' is the wordplay.
'initially' indicates taking the first letters.
The initial letters of 'politician easily wins' is 'PEW'.
(Other definitions for pew that I've seen before include "Long bench in a church" , "Part of flock sitting here" , "Long church seat" , "Where some of the flock rest" , "Bench-like seat in a church" .)