Lighthouse light (6)
I believe the answer is:
beacon
'lighthouse light' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for beacon that I've seen before include "Signal fire - signalling buoy" , "Prominent light on a hill" , "Signal fire - lighthouse" , "Shining light (on top of a hill?)" , "Raised signal fire or light" .)