About fifty vie to be perfect (8)
I believe the answer is:
complete
'be perfect' is the definition.
('complete' can be similar in meaning to 'perfect')
'about fifty vie' is the wordplay.
'about' is an insertion indicator.
'fifty' becomes 'l' (roman numeral).
'vie' becomes 'compete' ('compete' can be a synonym of 'vie').
'l' inserted inside 'compete' is 'COMPLETE'.
'to' is the link.
(Other definitions for complete that I've seen before include "Whole and unabridged" , "Finished, entire" , "Whole, entire, uncut" , "Finish; whole" , "Whole, nothing missing" .)