Phantom in sight! (6)
I believe the answer is:
vision
This clue is a double definition.
'phantom' is the first definition.
(thesaurus)
'sight' is the second definition.
(I know that sight can be written as vision)
'in' is the link.
(Other definitions for vision that I've seen before include "Dream" , "Vivid mental image" , "ideal?" , "Eyesight" , "Forward plan" .)