Where does “poena” come from?

poena (Latin) comes from Ancient Greek ποινή, from Proto-Hellenic kʷoinā́, from Proto-Indo-European kʷoynéh₂, from Proto-Indo-European kʷey- — to pay; to avenge.

Ancestry of “poena”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	ποινή	blood money, wergeld; fine, ransom, penalty,...
2	Proto-Hellenic	kʷoinā́	—
3	Proto-Indo-European	kʷoynéh₂	payment; punishment, vengeance
4	Proto-Indo-European	kʷey-	to pay; to avenge

Every word from Proto-Indo-European kʷey- →

poena — Etymology, Origin & Word History | Etymology Explorer