To be too late or too slow (i.e., beyond an acceptable or useful time); literally 'too late' (built from '遅い' + 'すぎる').
出発が遅すぎると飛行機に間に合わないよ。
If you leave too late, you won't make it to the plane.
その知らせを受け取ったときはもう手遅れで、遅すぎた。
By the time we received the news it was already too late.
練習が遅すぎると試合に勝つのは難しい。
If you start practicing too late, it's hard to win the match.
その薬は効果がないと言われ、治療開始が遅すぎた。
They said the medicine wouldn't work — the start of treatment was too late.