True Conservative shape (6)
I believe the answer is:
square
I believe this clue is a triple definition!
'true' is the first definition.
(thesaurus)
'conservative' is the second definition.
(I've seen this before)
'shape' is the third definition.
(squaring is a kind of shaping)
(Other definitions for square that I've seen before include "New York Times, for example" , "Londoners associate with Leicester" , "See 6" , "area of town" , "Four-sided, regular polygon" .)