Undress for southern journey (5)
I believe the answer is:
strip
'undress' is the definition.
(synonyms)
'southern journey' is the wordplay.
'southern' becomes 's' (abbreviation).
'journey' becomes 'trip' (trip is a kind of journey).
's'+'trip'='STRIP'
'for' acts as a link.
(Other definitions for strip that I've seen before include "Remove clothing" , "Team kit" , "Take off clothing" , "Remove clothes, just a sliver" , "Dismantle" .)