Set out to pry, when neighbour originally comes in for a bit (10)
I believe the answer is:
pennyworth
'a bit' is the definition.
The answer and definition can be both quantities as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'set out to pry when neighbour originally comes in' is the wordplay.
'set out' indicates anagramming the letters.
'originally' suggests taking the first letters.
'comes in' indicates putting letters inside.
The first letter of 'neighbour' is 'n'.
'to'+'pry'+'when'='toprywhen'
'toprywhen' is an anagram of 'penyworth'.
'penyworth' enclosing 'n' is 'PENNYWORTH'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for pennyworth that I've seen before include "may show value of thought" , "One's contribution to a discussion" , "A small amount" .)