Improvised score (7)
I believe the answer is:
scratch
This clue is a double definition.
'improvised' is the first definition.
(scratch can mean impromptu or unplanned)
'score' is the second definition.
(both can mean to mark or etch)
(Other definitions for scratch that I've seen before include "Graze" , "claw" , "Slight wound - withdraw from contest" , "Such a good golfer" , "Handicap where expected to make" .)