invalid vote; spoilt ballot; faulty ballot
Refers to a ballot that is not counted because it is incorrectly marked, damaged, or otherwise invalid. Used in election contexts.
There were many invalid votes in the election.
The number of spoilt ballots was 2% of the total.
Blank ballot; a ballot with no marks, which may be counted as invalid depending on the rules.
valid vote; valid ballot
Compound of 無効 (invalid) + 票 (ballot, vote).