YOU SAID:

That driver is a moron

INTO JAPANESE

その運転手は馬鹿だ

BACK INTO ENGLISH

That driver is stupid.

INTO JAPANESE

そのドライバーはばかです。

BACK INTO ENGLISH

That driver is an idiot.

INTO JAPANESE

その運転手はばかだ。

BACK INTO ENGLISH

That driver is an idiot.