Head of embassy has question about king for royal attendant (7)
I believe the answer is:
equerry
'royal attendant' is the definition.
(I've seen this before)
'head of embassy has question about king' is the wordplay.
'head of' suggests taking the first letters.
'has' means one lot of letters go next to another.
'question' becomes 'query' ('query' can be a synonym of 'question'**).
'about' is an insertion indicator.
'king' becomes 'r' (r is abbreviation for rex).
The initial letter of 'embassy' is 'e'.
'query' placed around 'r' is 'querry'.
'e'+'querry'='EQUERRY'
'for' is the link.
(Other definitions for equerry that I've seen before include "Officer attending a royal family member" , "Royal family official" , "Royal aide" , "Personal attendant of a member of the royal family" , "Sovereign's officer" .)