Ultimately not completely fair to a beginner (4)
I believe the answer is:
tyro
'a beginner' is the definition.
(I know that beginner can be written as tyro)
'ultimately not completely fair to' is the wordplay.
'ultimately' indicates one should take the final letters.
The last letters of 'not completely fair to' are 'TYRO'.
(Other definitions for tyro that I've seen before include "Neophyte" , "'Beginner, novice (4)'" , "Novice; Tory (anag.)" , "Apprentice" , "Spell for rookie" .)