Ill-fated United Nations woman entertaining king (7)
I believe the answer is:
unlucky
'ill-fated' is the definition.
(synonyms)
'united nations woman entertaining king' is the wordplay.
'united nations' becomes 'UN' (abbreviation).
'woman' becomes 'lucy' (woman's name).
'entertaining' indicates putting letters inside (inviting in, as for dinner).
'king' becomes 'K' (abbreviation for king in chess).
'lucy' going around 'k' is 'lucky'.
'un'+'lucky'='UNLUCKY'
(Other definitions for unlucky that I've seen before include "Not fortunate, ill-starred" , "Unfortunate" , "Not fortunate, hapless" , "Jinxed" , "Wretched" .)