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 wilie, from Old English wiliġe (“wicker basket”), from Proto-West Germanic *wiligijā, from Proto-Indo-European *weliko- (“willow-tree”). More at weel, willow.
Originally northern British usage, from the 1960s. Probably the simple use of a proper name as a pet name; compare dick, fanny and peter. Unlikely to be a contraction of Latin membrum virile, male member (that is, the penis), a Latin term used in English in the 19th century.
Meanings
(Australia, Ireland, New-Zealand, South-Africa, UK, childish, dialectal, slang) The penis.
Everybody knows your mum is a whore / Getting 'round Piccadilly looking for willy / Punters pull up and say "don't be silly" 2016 March 7, “Road Rage (Freestyle)”, performed by Little T (Josh Tate):
ceb badudoy (The penis) · nb guttetiss (The penis) · ab ата́џь (The penis) · pt pipi (The penis) · et noku (The penis) · sl lulček (The penis) · cs pinďour (The penis) · ru писю́н (The penis) · kl usuk (The penis) · it pipino (The penis) · hu kuki (The penis) · id burung (The penis) · hu fütyi (The penis) · ca tita (The penis) · pt bingola (The penis) · it pisellino (The penis) · fi pippeli (The penis) · cmn 弟弟 (The penis) · bg пи́шка (The penis) · nb tissemann (The penis) · se návli (The penis) · tr pipi (The penis) · fi pili (The penis) · ko 고추 (The penis) · ba бөстөр (The penis) · ru писю́нчик (The penis) · is typpi (The penis) · fr quéquette (The penis) · fo pittur (The penis) · da tissemand (The penis) · sq bibilush (The penis) · he בולבול (The penis) · sv pillesnopp (The penis) · ro pasăre (The penis) · fi kikkeli (The penis) · it pisello (The penis) · da dillermand (The penis) · nl piemel (The penis) · id titit (The penis) · pl siusiak (The penis) · es pito (The penis) · el πουλί (The penis) · acm بَلْبُولْ (The penis) · tr çük (The penis) · fr zizi (The penis) · de Pimmel (The penis) · sv snopp (The penis) · ja ちんちん (The penis) · la pipinna (The penis) · pt pirilau (The penis) · es pilila (The penis) · de Schniedel (The penis) · az duduş (The penis) · pl ptaszek (The penis) · se cihppa (The penis) · de Pullermann (The penis) · ga pilibín (The penis) · da diller (The penis) · ja おちんちん (The penis)
Perhaps a shortening of willy-nilly, an old way of saying “whether one wants to or not”, here referring to the person being used as an agent without their knowledge, i.e. regardless of their will.
Meanings
(UK, dialectal) A person who is manipulated into serving as a useful agent without knowing it.