Fairy for every one (4)
I believe the answer is:
peri
'fairy' is the definition.
(Persian mythological being)
'every one' is the wordplay.
'every' becomes 'per' (I've seen this in other clues).
'one' becomes 'i' (Roman numeral).
'per'+'i'='PERI'
'for' is the link.
(Other definitions for peri that I've seen before include "Fairy of Persian myth" , "Beautiful fairy-like creature" , "Mythical being" , "Ripe as a kind of fairy" , "Fairy queen" .)