1.
invalid, void, null and void
Having no legal force or effect; not valid. Used for contracts, tickets, votes, and other items that are no longer enforceable or usable.
この切符は無効です。
This ticket is invalid.
契約が無効になった。
The contract became void.
記入ミスがあった場合、その投票用紙は無効扱いとなります。
If there is a filling error, that ballot will be treated as invalid.
USAGE:
The antonym is 有効 (valid, effective). 無効 is used in legal, administrative, and technical contexts.
COMMON COLLOCATIONS:
- 無効になる: to become invalid
- 無効にする: to invalidate, to void
- 無効投票: invalid vote, spoiled ballot
- 契約無効: contract nullification
- 無効扱い: treated as invalid