Where does “whitnen” come from?

whitnen (Middle English) comes from Old Norse hvítna, from Proto-Germanic hwītnōną, from Proto-Indo-European kwind-.

Ancestry of “whitnen”, step by step

StepLanguageWordMeaning
1Old Norsehvítnato whiten
2Proto-Germanichwītnōnąto whiten, become white
3Proto-Indo-Europeankwind-—
Every word from Proto-Indo-European kwind- →Every word from Proto-Germanic hwītnōną →Every word from Old Norse hvítna →