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 judge whether this definition defines the answer.
'holding book describing champion?' is the wordplay.
'holding' means one lot of letters goes inside another.
'book' becomes 'b' (abbreviation for book).
'describing champion?' becomes 'uneaten' (I can't justify this - if you can you should believe this answer much more).
'b' going inside '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" .)