Left after a meal, holding book describing champion? (8)
I believe the answer is:
unbeaten
'left after a meal' is the definition.
I can't tell whether this defines the answer.
'holding book describing champion?' is the wordplay.
'holding' is an insertion indicator.
'book' becomes 'b' (abbreviation for book).
'describing champion?' becomes 'uneaten' (I can't explain this - if you can you should believe this answer much more).
'b' placed within 'uneaten' is 'UNBEATEN'.
Can you help me to learn more?
(Other definitions for unbeaten that I've seen before include "all-time" , "Yet to lose" , "Not yet defeated" , "never surpassed" , "Not having lost a match" .)