Asian pianist playing to entertain a king (9)
I believe the answer is:
pakistani
'asian' is the definition.
(I know that Pakistani is a type of asian)
'pianist playing to entertain a king' is the wordplay.
'playing' indicates an anagram.
'to entertain' indicates putting letters inside.
'king' becomes 'K' (abbreviation for king in chess).
'pianist' with letters rearranged gives 'pistani'.
'a'+'k'='ak'
'pistani' placed around 'ak' is 'PAKISTANI'.
(Other definitions for pakistani that I've seen before include "foreigner" , "National" , "One from Islamabad, say" , "from 16 [ISLAMABAD], perhaps" , "Eg, native of Islamabad" .)