Scoff as leader eliminated from qualifier (3)
I believe the answer is:
eat
'scoff' is the definition.
(I've seen this before)
'leader eliminated from qualifier' is the wordplay.
'leader eliminated from' means to remove the first letter (the letter which leads the word is removed).
'qualifier' becomes 'heat' (a heat is a qualifying round).
'heat' with its initial letter taken away is 'EAT'.
'as' is the link.
(Other definitions for eat that I've seen before include "Consume (food)" , "put away" , "Gobble up" , "Devour" , "Bite, chew and swallow" .)