Novice that you rule out initially (4)
I believe the answer is:
tyro
'novice' is the definition.
('tyro' can be a synonym of 'novice')
'that you rule out initially' is the wordplay.
'initially' indicates taking the first letters.
The initial letters of 'that you rule out' is 'TYRO'.
(Other definitions for tyro that I've seen before include "Neophyte" , "'Beginner, novice (4)'" , "Apprentice" , "Novice; Tory (anag.)" , "Spell for rookie" .)