windmill, n. — Green’s Dictionary of Slang

windmill n.

[SE wind + mill, i.e. the unpleasant odours]

the anus; thus she has no fortune but her mills, i.e. the windmill n. and watermill under water n.¹

1811		Lex. Balatronicum n.p.: Wind-Mill. The fundament. She has no fortune but her mills; i.e. she has nothing but her **** and a*se.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.

windmill soup (n.)

(Aus./US) insufficient food, i.e. ‘you‘ll get some if it goes round’.

1931		q. in I. Strauch Ashley Hall (2003) 57: [pic. caption] A joke in the 1931 Cerberus [college magazine] reads ‘What kind of soup do we have tonight’ [...] ‘Windmill soup [...] I’ll get some if it goes around’.
1932		Progressive Grocer 11 42/1: Lodger: ‘Bring some soup, please.’ Landlady: ‘What kind, sir? Windmill soup ?’ Lodger: ‘Windmill soup’ Landlady: ‘If it goes round, you get some’.
1941		A. Gurney Bluey & Curley 7 Nov. [synd. cartoon] — Gorblimey, windmill soup again!!! — What d’yer mean, windmill soup!!! — We’ll get some if it goes round!!!
1944		Medical World Oct. 480/1: Cook: ‘Windmill soup.’ Sergeant: ‘Windmill soup?’ Cook: ‘Sure. If it goes round you’ll get some’.
1970		Ford Times 63 19: Ellie: What’s windmill soup? Toby: Windmill soup? ... Well, if it goes around the table long enough, you might get some.
2006		P.M. Levitt Vaudeville Humor 219: This is windmill soup . You get some if it goes around.

have windmills in the head (v.) [Don Quixote’s ‘tilting at windmills’]

to entertain crazy notions, to fantasize.

1621		R. Burton ‘Democritus to Reader’ Anatomy of Melancholy (1893) I 74: He should have seen the wind-mills in one man’s head, an hornet’s nest in another!
1622		Massinger Virgin-Martyr II ii: Thy head is full of windmills.
1645		‘Fancies and Fantasticks’ Witts Recreations Y: A poets head is made of Match [...] Well may he grind his household bread, That hath a Wind-mill in his head.
1667		R. L’Estrange (trans.) Visions of Quevedo 305: I shall have never an Eye to see with [...] Wind-mills in my head.
c.1698		B.E. Dict. Canting Crew.
[1707		N. Ward London Terraefilius III 29: Your unintelligible Schemes [...] and your Nigromancick Jargons, which are all but the airy Notions of your own Windmill-Noddle].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.