Not exactly butter, but famously larger than life in fiction (6)
I believe the answer is:
bunter
'life in fiction' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'not exactly butter but famously larger' is the wordplay.
I cannot really understand how this works, but
'not' could be 'nt' (synonyms) and 'nt' is located in the answer.
This explanation may well be incorrect...
'than' acts as a link.
Can you help me to learn more?
(Other definitions for bunter that I've seen before include "Billy ..., the Owl of the Remove at Greyfriars" , "Unending time" , "Billy -, fict. schoolboy" , "Billy ......, iconic English fat boy" .)