Carriage set up or dismantled (7)
I believe the answer is:
Here is my best explanation:
'carriage' is the definition.
('posture' can be a synonym of 'carriage')
'set up or dismantled' is the subsidiary indication.
'dismantled' indicates anagramming the letters.
'setupor' anagrammed gives 'posture'.
(Other definitions for posture that I've seen before include "Bodily stance", "Way of bearing one's body", "Pose or position", "Body position", "Bodily position", "The way a person stands or sits", "Stance adopted by Proteus", "Carriage, attitude", "Disposition of the body found in pure sot" and "Carriage of Proteus".)