Author of nonsense new to master (5)
I believe the answer is:
learn
'master' is the definition.
(I've seen this before)
'author of nonsense new' is the wordplay.
'author of nonsense' becomes 'lear' (nonsense poet Edward Lear).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'lear'+'n'='LEARN'
'to' acts as a link.
(Other definitions for learn that I've seen before include "Be educated" , "Get to know" , "Come to know" , "what pupils do in schools" , "teach illiterate" .)