Learn Farsi: خداحافظ، آقا!

It literally means God be your protector. The word khoda means God, and hafez means protector or keeper. It is the standard and most common way to say goodbye in Farsi.

Why is there no letter for the o sound in the first part of khodahafez?

In Farsi, short vowels like a, e, and o are usually not written out in the alphabet. The o sound in khoda is a short vowel, so you only see the written consonants and long vowels.

Can I use agha by itself just like sir in English?

Yes! While agha translates to Mr. when put before a name, using it all by itself is a very polite and common way to address a man respectfully, exactly like sir.

Why does the first letter of agha have a little symbol over it?

That symbol over the letter alef is called a kolah, which means hat. It tells you to pronounce it as a long aa sound when it appears at the very beginning of a word.