Meaning and Usage
"無効" (むこう) means "invalid," "no effect," or "unavailable." It is often used in formal or technical contexts such as contracts, software, or official documents to indicate that something is not legally or functionally effective.
Common Contexts
You will frequently see "無効" used with things like coupons, passwords, contracts, or any situation where validity or authorization is required. It implies that the item or action cannot be used or recognized as legitimate.
Collocations and Patterns
- 無効になる: to become invalid (e.g., a password or ticket)
- 無効とする: to declare something invalid (e.g., a contract)
- 無効なクーポン: an invalid coupon
Register and Nuance
"無効" is a formal term and is not typically used in casual conversation. It carries a clear, official tone. Avoid confusing it with "無効化" which means "to invalidate" or "disable" something actively.
Common Mistake
Learners sometimes confuse "無効" with "無効化." Remember that "無効" describes the state of being invalid, while "無効化" refers to the action of making something invalid.