Has improperly won a point (4)
I believe the answer is:
owns
'has' is the definition.
('own' can be a synonym of 'have')
'improperly won a point' is the wordplay.
'improperly' indicates an anagram (I've seen this in other clues).
'a point' becomes 's' (S is an example**).
'won' is an anagram of 'own'.
'own'+'s'='OWNS'
(Other definitions for owns that I've seen before include "Confesses" , "Has possession of by right" , "Belongs to" , "uses" , "Admits possession" .)