Sirius or Polaris (4)
I believe the answer is:
star
I believe this clue is a double definition.
'sirius' is the first definition.
(thesaurus)
'polaris' is the second definition.
(I've seen this in another clue)
(Other definitions for star that I've seen before include "Celebrated actor - heavenly body!" , "Ball of fire" , "Celebrity's" , "Chaste, pure" , "Cult sci-fi film" .)