Willy

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early 20th century: pet form of the given name William .

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From Middle English willy, willi, equivalent to will +‎ -y. Cognate with Dutch willig(“obedient, hearsome”), German willig(“willing”), Swedish villig(“willing, agreeable”).

From Middle English wilȝe, from Old English wiliġ(“willow”). More at willow.

From Middle English wilie, from Old English wiliġe, wileġe(“basket”), from Proto-Germanic *wiligō(“wicker basket”), from Proto-Indo-European *weliko-(“willow-tree”). More at weel, willow.

willy (plural willies)

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)