Star in Cygnus (5)
I believe the answer is:
deneb
'star in cygnus' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for deneb that I've seen before include "First magnitude star in Cygnus" , "Be Ned (anag) - brightest star in Cygnus" , "Bright star in Cygnus" , "Bright star; be end (anag.)" , "The star Alpha Cygni" .)