Unfashionable job in a frontier settlement (7)
I believe the answer is:
outpost
'a frontier settlement' is the definition.
('outpost' can be a synonym of 'frontier settlement')
'unfashionable job' is the wordplay.
'unfashionable' becomes 'out' ('out' can be a synonym of 'unfashionable').
'job' becomes 'post' (post is a kind of job**).
'out'+'post'='OUTPOST'
'in' is the link.
(Other definitions for outpost that I've seen before include "A distant branch or settlement" , "Small camp some distance away from the main army" , "isolated stronghold" , "Remote branch" , "Remote place" .)