忽こつ然ぜん

taru-adjective, adverb taking the 'to' particle

suddenly; abruptly; unexpectedly

Literary or formal adverb describing something happening all at once, often with a dramatic or surprising nuance. Commonly used with と (忽然と).

• 彼かれは忽こつ然ぜんと姿すがたを消けした。

  He suddenly vanished.

• 忽こつ然ぜんとして霧きりが立たちこめた。

  Suddenly, a fog rolled in.