極きょく端たんに走はしる

expression, godan verb (-ru)

go to extremes; go too far; go overboard

Used when someone takes an action or opinion to an unreasonable extreme, often with a negative connotation.

• 彼かれは節せつ約やくに極きょく端たんに走はしって、必ひつ要ようなものまで買かわなくなった。

  He went to extremes with saving money and stopped buying even necessities.

• ダイエットで極きょく端たんに走はしると、健けん康こうを害がいするよ。

  If you go overboard with dieting, you'll harm your health.