completely wrong
Avevo torto marcio e devo ammetterlo senza cercare scuse inutili questa volta.
I was dead wrong and I have to admit it without making useless excuses this time.
Hai torto marcio e lo sai benissimo.
You're dead wrong and you know it.
Aveva torto marcio e non voleva ammetterlo davanti a nessuno.
He was dead wrong and he didn't want to admit it to anyone.
He’s completely in the wrong.