Where does “Hun” come from?

Hun (Middle English) comes from Old English Hūnas, from Latin Hunni, from Ancient Greek Οὗννος — Hun.

Ancestry of “Hun”, step by step

Step	Language	Word	Meaning
1	Old English	Hūnas	—
2	Latin	Hunni	Huns
3	Ancient Greek	Οὗννος	Hun

Hun — Etymology, Origin & Word History | Etymology Explorer