Pole that is restricting a traveller (6)
I believe the answer is:
roadie
'traveller' is the definition.
(someone who goes on tour with a musician)
'pole that is restricting a' is the wordplay.
'pole' becomes 'rod' (synonyms).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'restricting' is an insertion indicator.
'rod'+'ie'='rodie'
'rodie' enclosing 'a' is 'ROADIE'.
(Other definitions for roadie that I've seen before include "Member of rock band's crew" , "Band crew member" , "Worker with band on tour" , "Movement into a place" , "help with the group" .)