Flying island in "Gulliver's Travels" (6)
I believe the answer is:
laputa
'flying island in gulliver's travels' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for laputa that I've seen before include "Swift's flying island" , "Flying island in Gulliver's Travels" , "Gulliver's flying city" , "Imaginary island" , "Flying island visited by Gulliver" .)