Star not quite convert to compassionate eating? (4)
I believe the answer is:
vega
'star' is the definition.
(star in the constellation Lyra)
'not quite convert to compassionate eating?' is the wordplay.
'not quite' means to remove the last letter (most but not all of the word).
'convert to compassionate eating?' becomes 'vegan'.
'vegan' with its last letter removed is 'VEGA'.
(Other definitions for vega that I've seen before include "Gave turn to a star" , "First magnitude star" , "Star in Lyra; grassy plain (Spanish)" , "Bright star of constellation Lyra" , "Brightest star of constellation Lyra" .)