みだりに

みだりに
adverb
without good reason; recklessly; thoughtlessly
formaldescriptive
1. without good reason; recklessly; thoughtlessly
Doing something carelessly, arbitrarily, or without proper justification. Often appears on signs and in regulations prohibiting an action without due cause.
Please do not touch without good reason.
You must not disclose personal information without proper cause.
Making loud noises inside the facility without good reason is prohibited.

Stiff, formal register — common in posted notices, regulations, and legal language. The kanji form (みだ) or (みだ) exists but is rarely used; kana is the standard.

Common collocations

Similar words

  • 勝手(かって): as one pleases — more casual, focuses on selfishness rather than legitimacy
  • 無断(むだん): without permission — emphasizes lack of approval, more specific
  • やたら: indiscriminately, excessively — colloquial, focuses on frequency or volume