What a trip!
I believe the answer is:
odyssey
'what a trip' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for odyssey that I've seen before include "Greek epic on the wanderings of Ulysses" , "Long, eventful, wandering journey" , "Homer's epic poem" , "Gruelling journey as by Homer" , "Homer's epic poen about great journey" .)