United Nations entertaining the Spanish writer (6)
I believe the answer is:
belloc
'writer' is the definition.
(hilaire belloc)
'united nations entertaining the spanish' is the wordplay.
'united nations' becomes 'bloc' (I've seen this before).
'entertaining' means one lot of letters goes inside another.
'the spanish' becomes 'el'.
'bloc' placed around 'el' is 'BELLOC'.
(Other definitions for belloc that I've seen before include "Hilaire -, Eng. author known for comic verse" , "Hilaire -, author, MP" , "Hilaire --, writer" , "poet" , "Hilaire -, English author" .)