A windfall may be unwelcome at this sporting function (7)
I believe the answer is:
regatta
'a windfall may be unwelcome at this sporting function' is the definition.
The definition suggests a singular noun which matches the answer.
'at this sporting function' is the wordplay.
I cannot really understand how this works, but
'at' is within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for regatta that I've seen before include "Meeting at Dartmouth, perhaps" , "Rowing, sailing, gala" , "which may involve eights" , "Sports event" , "Craft meeting" .)