Star Victor Mature making a comeback (4)
I believe the answer is:
vega
'star' is the definition.
(star in the constellation Lyra)
'victor mature making a comeback' is the wordplay.
'victor' becomes 'V' (phonetic alphabet: alpha, bravo, charlie etc.).
'mature' becomes 'age' (synonyms).
'making a comeback' says the letters should be written in reverse.
'age' reversed gives 'ega'.
'v'+'ega'='VEGA'
(Other definitions for vega that I've seen before include "Bright star of constellation Lyra" , "Star in Lyra; grassy plain (Spanish)" , "heavenly body" , "Gave turn to a star" , "Brightest star of constellation Lyra" .)