Publicize policy for carrier (7)
I believe the answer is:
airline
'carrier' is the definition.
(airline is a kind of carrier)
'publicize policy' is the wordplay.
'publicize' becomes 'air' (synonyms).
'policy' becomes 'line' (I've seen this in another clue).
'air'+'line'='AIRLINE'
'for' acts as a link.
(Other definitions for airline that I've seen before include "carrier" , "It serves both divers and travellers" , "EasyJet, for example" , "Aircraft operating company" , "Transport organisation" .)