Walton loses points as a singer (4)
I believe the answer is:
alto
'a singer' is the definition.
(type of singing voice)
'walton loses points' is the wordplay.
'loses' is a deletion indicator.
'points' becomes 'wn' (two compass points).
'walton' with 'wn' removed is 'ALTO'.
'as' is the link.
(Other definitions for alto that I've seen before include "Lowest female singing voice" , "Woman's singing voice" , "Singer's hidden inside chemical toilet" , "A singing voice or pitch" , "Low female singing voice" .)