Leave, taking universal article as waste (5)
I believe the answer is:
guano
'waste' is the definition.
(I know that guano is a type of body waste)
'leave taking universal article' is the wordplay.
'leave' becomes 'go' (to go is to depart or leave).
'taking' means one lot of letters goes inside another.
'universal' becomes 'u'.
'article' becomes 'an' (indefinite article).
'u'+'an'='uan'
'go' enclosing 'uan' is 'GUANO'.
'as' acts as a link.
(Other definitions for guano that I've seen before include "Bird droppings used as fertiliser" , "MP's first address to House" , "Manure from sea birds" , "Manure from seabird or bat" , "Fertiliser made from seabird droppings" .)