Excursion is returning, touring a long way away (6)
I believe the answer is:
safari
'excursion' is the definition.
(thesaurus)
'is returning touring a long way away' is the wordplay.
'returning' says the letters should be written in reverse.
'touring' indicates putting letters inside (touring can mean going round).
'a long way away' becomes 'afar' (I've seen this in another clue).
'is' written backwards gives 'si'.
'si' going around 'afar' is 'SAFARI'.
(Other definitions for safari that I've seen before include "Hunting journey" , "tropical trip" , "Hunting expedition (in Africa)" , "Big game expedition" , "Animal expedition" .)