Ordinary members (4,3,4)
I believe the answer is:
rank and file
'ordinary members' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rank and file that I've seen before include "controlled by the castle" , "Ordinary people as opposed to their leaders" , "The board is made up of such" , "Ordinary men" , "seen on a chessboard" .)