Plump, a Parisian in bar (5)
I believe the answer is:
round
'plump' is the definition.
(plump can mean round or full)
'a parisian in bar' is the wordplay.
'a parisian' becomes 'un' ('a' in French).
'in' indicates putting letters inside.
'bar' becomes 'rod' (both can mean a pole or stick).
'un' inserted inside 'rod' is 'ROUND'.
(Other definitions for round that I've seen before include "Piece of ammunition" , "Piece of boxing" , "Set of drinks; song" , "Get applause" , "The canon" .)