How to say "unintended" in Japanese

• 無作為むさくいCommon
  no-adjective, na-adjectiveReally means 'random': chosen or occurring without deliberate design, as in statistics. For most senses of 'unintended' this is not the word you want; it fits what happens haphazardly, not what one regrets.
  アンケート用よう紙しが無作為むさくいに配布はいふされた。↗

  The questionnaires were distributed at random.
• 不本意ふほんいCommon
  na-adjective, nounThe word for what happens against one's real wishes: reluctant, unwilling, regrettable. Fits unintended outcomes one did not want and accepts with disappointment, such as reluctantly settling for a second-best choice.
  彼女かのじょは不本意ふほんいながらもそうした。↗

  She did it against her will.

Choose 不本意 for the regretful sense — outcomes or actions contrary to one's real wishes, reluctant or unwilling; choose 無作為 for the random, haphazard sense of something done or occurring without deliberate design.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 無作為むさくいrandom
• 不本意ふほんいreluctant