Spare not included (5)
I believe the answer is:
extra
I believe this clue is a double definition.
'spare' is the first definition.
(I know that spare can be written as extra)
'not included' is the second definition.
(I've seen this before)
(Other definitions for extra that I've seen before include "Accessory" , "entry on scorecard?" , "wide? It could be" , "lesser player" , "fortuitous run" .)