Party disrobing heir in spoilt child (7)
I believe the answer is:
ceilidh
'party' is the definition.
(I've seen this before)
'disrobing heir in spoilt child' is the wordplay.
'disrobing heir' becomes 'ei' (I can't explain this - if you can you should believe this answer much more).
'in' is an insertion indicator.
'spoilt' is an anagram indicator.
'child' with letters rearranged gives 'clidh'.
'ei' placed within 'clidh' is 'CEILIDH'.
Can you help me to learn more?
(Other definitions for ceilidh that I've seen before include "Gaelic social event" , "Irish night out" , "Celtic evening with folk music and dancing" , "Celtic folk music event" , "Informal gathering for traditional Irish song and dance" .)