Nelson Eddy's donkey (5)
I believe the answer is:
neddy
'donkey' is the definition.
(I've seen this before)
'nelson eddy's' is the wordplay.
'nelson' becomes 'n' (this might be a standard abbreviation which I don't know about).
'n'+'eddy'='NEDDY'
Can you help me to learn more?
(Other definitions for neddy that I've seen before include "Donkey (colloq.)" , "One of child's 23 ac" .)