50-50 about a sports jacket feature (5)
I believe the answer is:
lapel
'jacket feature' is the definition.
(I've seen this in another clue)
'50-50 about a sports' is the wordplay.
'50' becomes 'l' (Roman numeral).
'50' becomes 'l' (Roman numeral).
'about' says to put letters next to each other.
'sports' becomes 'pe' (Physical Education).
'a'+'pe'='ape'
'l' put after 'ape' is 'apel'.
'l'+'apel'='LAPEL'
(Other definitions for lapel that I've seen before include "Lower extension of collar on jacket or coat" , "top of coat" , "Extended part of a collar" , "Folded-back part of coat" , "Jacket fold" .)