Jury member, in theory (4)
I believe the answer is:
peer
'jury member in theory' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for peer that I've seen before include "Look searchingly at lord?" , "unelected politician" , "Look hard at the nobleman" , "Struggle to see; equal" , "Member of the nobility" .)