Costs hit this nationality badly (8)
I believe the answer is:
scottish
'costs hit this nationality badly' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for scottish that I've seen before include "northern folk" , "From north of the border" , "Caledonian" , "So stitch up to be like Angus or Jock" , "From the northern UK" .)