Pundit to knock rest off (7)
I believe the answer is:
tipster
'pundit' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'knock rest off' is the wordplay.
'knock' becomes 'tip' (I am not sure about this - if you are sure you should believe this answer much more).
'off' indicates an anagram.
'rest' is an anagram of 'ster'.
'tip'+'ster'='TIPSTER'
'to' is the link.
Can you help me to learn more?
(Other definitions for tipster that I've seen before include "One who sells betting advice" , "Person offering advice" , "Person who points out likely race winners" , "Seller of information on racecourse etc" , "he recommends risky investments" .)