One who likes to scorn club first (7)
I believe the answer is:
Here is my best explanation:
'one who likes to scorn' is the definition.
'club first' is the subsidiary indication.
'club' becomes 'iron' (iron is a kind of club).
'first' becomes 'ist'.
(Other definitions for ironist that I've seen before include "One using opposites to humorous effect", "One speaking with hidden meaning", "Quasi-satirical humorist", "Swift, for one", "One using a form of satire", "Satirical speaker", "Mark Antony when making speech" and "A contrary speaker".)