My relative at the United Nations is inside (4)
I believe the answer is:
aunt
'my relative' is the definition.
I can't tell whether this definition defines the answer.
'at the united nations is inside' is the wordplay.
'the united nations' becomes 'UN' (abbreviation).
'is inside' is an insertion indicator.
'at' placed around 'un' is 'AUNT'.
Can you help me to learn more?
(Other definitions for aunt that I've seen before include "Parent's female sibling" , "Tuna for the odd relative" , "kinswoman" , "Tuna (anag.)" , "Charley's in play?" .)