思わず|おもわずomowazu[2]nakadaka (mid-high)

1. adverbunconsciously; involuntarily; instinctively; reflexively; spontaneously; unintentionally; in spite of oneself
   彼かれは思おもわず笑わらった。↗

   He laughed in spite of himself.

• Synonym我知らずわれしらずWrittenWritten and strongly literary: doing something unconsciously, before you know it or can help it, as in 「我知らず涙がこぼれた」.
• Synonym我にもなくわれにもなくWrittenWritten: involuntarily acting unlike your usual self, as in 「我にもなく取り乱す」; carries a nuance of uncharacteristic behavior.
• Synonym覚えずおぼえずWrittenWritten and more old-fashioned than 「思わず」: doing something without noticing or intending to. In everyday speech, say 「思わず」.
• RelatedついNeutralColloquial: doing something by slip or without thinking, as in 「つい食べ過ぎる」, often what you know you shouldn't; 「思わず」 stresses a split-second reaction instead.
• AntonymわざとNeutralOn purpose, as in 「わざと負ける」 — the opposite of 「思わず」's unconscious reaction; common in colloquial speech.
• Antonym意図してNeutralDeliberately, on purpose — the direct opposite of the involuntary, spur-of-the-moment 「思わず」.

For a momentary involuntary reaction, use 「思わず」; for giving in to something you know you shouldn't, 「つい」; in written prose, 「我知らず」. For deliberate action, use 「わざと」.

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

1. そのつもりではないのに無意識むいしきにそうなる様子ようす。つい。しらずしらず。うっかり。