How many in favour of restraining the union? (4)
I believe the answer is:
four
'how many' is the definition.
I can't tell whether this defines the answer.
'in favour of restraining the union?' is the wordplay.
'in favour of' becomes 'for' (being for a particular cause).
'restraining' is an insertion indicator.
'the union?' becomes 'U' (common abbreviation as in Trades Union Congress).
'for' enclosing 'u' is 'FOUR'.
Can you help me to learn more?
(Other definitions for four that I've seen before include "An even number" , "Boundary hit (cricket)" , "Square number" , "10 cleared of misuse of fortune" , "Number of players in a doubles game" .)