詩だ

is a poem

→ 詩
phrase Uncommon #13,930
is a poem 詩 means “poem,” and だ is the plain-form copula meaning “is.” The phrase can also be understood as “it’s poetic” depending on context.
JA: これはただの詩だ。
EN: This is just a poem.

奴の自作詩だ

It's a poem he wrote himself.

— いまを生きる (1989)

君の事を歌ったよう詩だ

It’s a poem that seems to have been written about you.

— さらば、わが愛/覇王別姫 (1993)

素晴らしい詩だでしょ

It's a wonderful poem, isn't it?

— カンフーハッスル (2004)

詩だ

It's a poem!

— いまを生きる (1989)

あれは大した詩だ

That’s quite a poem.

これは詩だ

This is a poem.

— イル・ポスティーノ (1994)

歌う発見があればすべてが詩だ

If you discover something that sings of cats, flowers, and rain, everything becomes poetry.

— いまを生きる (1989)

まるで詩だ

It’s like poetry.

— レミーのおいしいレストラン (2007)

バスコ応える詩だ

It’s a poem in response to Vasco.

— 雪山の絆 (2023)

ホイットマン詩だ

It's a poem by Whitman.

— いまを生きる (1989)

いい詩だ

It's a good poem.

— イル・ポスティーノ (1994)

海の詩だけれどあなたに捧げたあなたがいなかったらなど書かなかった

It is a poem about the sea—but I would never have written poetry if you, to whom I dedicated it, had not existed.

— イル・ポスティーノ (1994)