ひとりでに・独りでに・一人でにhitorideni[0]heiban (flat)

1. adverbby itself; automatically; naturally
   ろうそくはひとりでに消きえた。↗

   The candle went out of itself.

• SynonymおのずからWrittenNaturally; synonymous with 「自ずと」 but used mainly in written or formal prose, as in 「自ずから明らか」.
• Synonym自ずとおのずとNeutralNaturally; mostly for results or things that follow logically, as in 「自ずと答えが見える」. 「ひとりでに」 stresses no outside force, like a door opening or a wound healing.
• Antonym故意にこいにNeutralDeliberately, on purpose; the neutral opposite of 「ひとりでに」's natural, unplanned happening.
• Antonym人為的にWrittenArtificially, by human intervention; the written-language opposite of 「ひとりでに」, which is about things happening naturally on their own.

Use 「ひとりでに」 for something happening by itself without outside force, as in 「ドアがひとりでに開いた」 or 「涙がひとりでに出る」. For results or truths emerging naturally, use 「自ずと」 (「自ずから」 in formal prose); opposites are 「故意に」 (deliberately) and 「人為的に」 (artificially).

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

1. 他ほかからの力ちからなしにある状態じょうたいになったり、あることが行おこなわれる様さま。