Knock back doctor in nursing academy (5)
I believe the answer is:
drain
'knock back' is the 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?
'doctor in nursing academy' is the wordplay.
'doctor' becomes 'd' (eg in PhD, Doctor of Philosophy).
'nursing' indicates putting letters inside.
'academy' becomes 'RA' (abbreviation for Royal Academy).
'd'+'in'='din'
'din' enclosing 'ra' is 'DRAIN'.
Can you help me to learn more?
(Other definitions for drain that I've seen before include "Something using up resources" , "Waste pipe" , "Empty of liquid" , "Wasted down here" , "Gutter" .)