It may be thrown after a wedding (9)
I believe the answer is:
reception
This clue might be a double definition.
'it may be thrown' is the first definition.
The definition suggests a singular noun which matches the answer.
'a wedding' is the second definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'after' is the link.
Can you help me to learn more?
(Other definitions for reception that I've seen before include "Formal function" , "How one is greeted" , "First class" , "class of youngsters" , "A social event" .)