Picture firm haggle regularly (5)
I believe the answer is:
image
'picture' is the definition.
('image' can be a synonym of 'picture')
'firm haggle regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'firm'+'haggle'='firmhaggle'
The alternate letters of 'firmhaggle' are 'IMAGE'.
(Other definitions for image that I've seen before include "Dead ringer" , "Likeness U symbol" , "Mental or physical representation" , "Simile, metaphor" , "Effigy, icon" .)