Made off without us, feeling tickled (6)
I believe the answer is:
amused
'feeling tickled' is the definition.
'made off without us' is the wordplay.
'off' indicates an anagram.
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'made' with letters rearranged gives 'amed'.
'amed' going around 'us' is 'AMUSED'.
(Other definitions for amused that I've seen before include "Beguiled" , "Queen Victoria wasn't!" , "Victoria reputedly wasn't" , "Pleasantly occupied" , "Delighted" .)