Used to be cool to carry loaded gun in cleansing operation (7-2)
I believe the answer is:
washing-up
'cleansing operation' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'used to be cool to carry loaded gun' is the wordplay.
'used to be' becomes 'was' (eg 'he was...' means 'he used to be...').
'cool' becomes 'hip' (hip can mean cool or fashionable).
'to carry' indicates putting letters inside.
'loaded' indicates an anagram (loaded can mean drunk).
'gun' is an anagram of 'ngu'.
'hip' enclosing 'ngu' is 'hingup'.
'was'+'hingup'='WASHING-UP'
'in' is the link.
Can you help me to learn more?
(Other definitions for washing-up that I've seen before include "Dirty crockery, etc." , "Kitchen chore" , "Kitchen task" .)