"____ Horizon" (4)
'horizon' is the definition.
(I know that horizon can be written as skyline)
This is the entire clue.
(Other definitions for skyline that I've seen before include "Horizon; like NY's (anag.)" , "Visible horizon" , "Outline of hills or buildings against firmament" , "Silhouette or outline of buildings" , "City horizon" .)
(Other definitions for lost that I've seen before include "Not knowing one's whereabouts" , "Unable to find one's way" , "See 10" , "Mislaid or astray" , "Not having known where one is" .)