For these people, southwest is south! (5)
I believe the answer is:
swiss
'for these people' is the definition.
The definition suggests an adverb but the answer is not.
'southwest is south' is the wordplay.
'southwest' becomes 'SW' (synonyms).
'south' becomes 's' (abbreviation).
'sw'+'is'+'s'='SWISS'
Can you help me to learn more?
(Other definitions for swiss that I've seen before include "Like William Tell" , "One from Basle" , "Sort of roll, of papal Guard" , "Mid-European" , "Nationality of Carl Jung" .)