はまったく別だ

is completely different

→ は

phrase Rare #36,515

is completely different Used to emphasize that two things are distinct or should not be confused. まったく means “completely,” and 別 means “different” or “separate.”

JA: 考えることと行動することはまったく別だ。

EN: Thinking and taking action are completely different things.

知っていることと教えることはまったく別だ。

Knowing something and teaching it are two completely different things.

計画をたてることと実行することとはまったく別だ。

Planning and carrying out a plan are two completely different things.

いう事と行う事はまったく別だ。

Saying something and doing it are two entirely different things.

君の動機はまったく別だ

Your motives are completely different.

— 暗殺の森 (1971)