脱だっ線せん行こう為い

noun

aberrant behavior; escapade; acting out

Figurative use of 'derailment act'; describes behavior that deviates from expected norms, often in a social or moral context. Can range from mild eccentricity to serious misconduct.

• 彼かれの脱だっ線せん行こう為いには周しゅう囲いも呆あきれている。

  People around him are fed up with his aberrant behavior.

• 会かい議ぎ中ちゅうに突とつ然ぜん歌うたい出だすなんて、完かん全ぜんな脱だっ線せん行こう為いだ。

  Suddenly starting to sing during a meeting is a complete escapade.