Ira intent on upsetting the traveller (9)
I believe the answer is:
itinerant
'the traveller' is the definition.
(itinerant is a kind of traveller)
'ira intent on upsetting' is the wordplay.
'on' means one lot of letters go next to another.
'upsetting' indicates an anagram.
'ira' after 'intent' is 'intentira'.
'intentira' anagrammed gives 'ITINERANT'.
(Other definitions for itinerant that I've seen before include "Tie-in rant to a traveller" , "(Person) on the move" , "Travelling from place to place" , "Old labourer/traveller who travelled from place to place" , "Moving from place to place" .)