King John's brother (7)
I believe the answer is:
richard
'king john's brother' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for richard that I've seen before include "Name of three English kings" , "Cliff --; -- Wagner" , "Boy's name - Cliff?" , "& 20 Down US President" , "Play about hunchback" .)