Pole, Frenchman, colonist and soldier (5,8)
I believe the answer is:
staff sergeant
'soldier' is the definition.
(staff sergeant is a military rank)
'pole frenchman colonist' is the wordplay.
'pole' becomes 'staff'.
'frenchman' becomes 'serge' (Serge is a common French name).
'colonist' becomes 'ant' (ants live in colonies).
'staff'+'serge'+'ant'='STAFF SERGEANT'
'and' acts as a link.
(Other definitions for staff sergeant that I've seen before include "A senior NCO" , "NCO rank" , "Officer" , "person of rank" .)