すんだ

was over, was finished, was settled

→ 済む
すん manage without having to; get by with + だ Plain copula (nonpast)
verb · informal, past tense Rare #32,233
was over, was finished, was settled Usually written 済んだ.
JA: 宿題はもうすんだ。
EN: The homework is already done.
Conjugation of 済む

若い僕らは、こういう言い方をすんだよ。

This is how young people like us say it.

彼は警告ですんだ。

He got off with a warning.

その話はすんだよ

That matter is settled.

— ザ・マン・フロム・アース (2007)

演奏会がすんだときに、聴衆は拍手した。

When the concert ended, the audience applauded.

すんだんだ

It’s over.

— 東京物語 (1953)

すんだことだ

It's in the past.

— Arrietty (2010)