Streaker in the sky (6)
I believe the answer is:
meteor
'streaker in the sky' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for meteor that I've seen before include "Small piece of matter in the solar system" , "Remote (anag)" , "Body falling from space" , "streaker?" , "Glowing body entering atmosphere" .)