Noble expected to embrace king (4)
I believe the answer is:
duke
'noble' is the definition.
(duke is a kind of noble)
'expected to embrace king' is the wordplay.
'expected' becomes 'due' (similar in meaning).
'to embrace' is an insertion indicator.
'king' becomes 'k' (chess abbreviation).
'due' placed around 'k' is 'DUKE'.
(Other definitions for duke that I've seen before include "Highest ranking British peer" , "noble" , "Lord" , "Nickname of John Wayne" , "Highest-ranking nobleman" .)