Nobleman playing Lear? (4)
I believe the answer is:
earl
'nobleman' is the definition.
(earl is a kind of nobleman)
'playing lear?' is the wordplay.
'playing' is an anagram indicator.
'lear' with letters rearranged gives 'EARL'.
(Other definitions for earl that I've seen before include "Countess his wife" , "Aristocrat ranking between marquis and viscount" , "One who's been elevated" , "Titled man" , "A real peer" .)