Dictionary / Vocabulary / 今更
いまさら
now (when it is already much too late); at this stage; afresh; anew
JLPT N1 common word Also written 今さら
今更悔やんでも後の祭りだ。
It is too late to repent.
今更そんなことを言った日にゃ、火に油を注ぐことになるだけだよ。
For you to come out and say that kind of thing now would just be pouring oil on the fire.
今さら騒いでもどうにもならないよ。後の祭りだよ。
Yelling about it won't help now. You should have done that when it counted.