Rising impudence over dour traveller (7)
I believe the answer is:
pilgrim
'traveller' is the definition.
(pilgrim is a kind of traveller)
'rising impudence over dour' is the wordplay.
'rising' says the letters should be written backwards (going up in a down clue).
'impudence' becomes 'lip' (lip is a kind of impudence).
'over' means one lot of letters go next to another.
'dour' becomes 'grim' ('grim' can be a synonym of 'dour').
'lip' in reverse letter order is 'pil'.
'pil'+'grim'='PILGRIM'
(Other definitions for pilgrim that I've seen before include "Seeker" , "Wanderer" , "Traveller (who made Progress?)" , "One progressive type" , "Traveller in sacred place for religious reasons" .)