It transpires in waste disposal (5)
I believe the answer is:
sweat
'disposal' 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?
'it transpires in waste' is the wordplay.
'waste' can be anagrammed to 'SWEAT'.
Though, I am not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for sweat that I've seen before include "Male perspiration?" , "Soldier" , "Salty fluid secreted by glands" , "Perspire" , "Trouble in Australia" .)