Specialist brought to western front (4)
I believe the answer is:
prow
'front' is the definition.
(I know that prow is a type of front)
'specialist brought to western' is the wordplay.
'specialist' becomes 'pro' (I've seen this in another clue).
'brought to' means one lot of letters go next to another.
'western' becomes 'w'.
'pro'+'w'='PROW'
(Other definitions for prow that I've seen before include "Bow of a vessel" , "Bow of a ship" , "Ship's front part" , "Boat's bow" , "position of figurehead" .)