Celsius, but not Fahrenheit (5)
I believe the answer is:
swede
'celsius but not fahrenheit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for swede that I've seen before include "Scandinavian; root veg." , "Man from Malmo" , "Foreigner" , "Large root vegetable" , "North European" .)