Take off south on journey (5)
I believe the answer is:
strip
'take off' is the definition.
(stripping is a kind of taking off)
'south on journey' is the wordplay.
'south' becomes 's' ('S' can be a synonym of 'south').
'on' means one lot of letters go next to another.
'journey' becomes 'trip' (trip is a kind of journey).
's'+'trip'='STRIP'
(Other definitions for strip that I've seen before include "Series of cartoons" , "footballers' outfit" , "Undress (provocatively)" , "Team kit" , "Remove covering from" .)