Look pronouncedly like a king of the theatre (4)
I believe the answer is:
leer
'look' is the definition.
(leering is a kind of looking)
'pronouncedly like a king of the theatre' is the wordplay.
I cannot quite understand how this works, but
'king' could be 'er' (I've seen this in other clues) and 'er' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for leer that I've seen before include "Lascivious gaze" , "Ogle, smirk" , "unpleasant look" , "Stare suggestively" , "Look suggestively" .)