Green’s Dictionary of Slang

attic n.

1. (orig. boxing, also top-loft) the head.

[UK]‘A Pembrochian’ Gradus ad Cantabrigiam 129: Cram not your attics / With dry mathematics.
[UK]‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc.
[UK]Swell’s Night Guide 108/2: Attic, the head, brain pan, the knob, the nut, the canister.
[UK]Hotten Dict. of Modern Sl. etc.
[US]Letters by an Odd Boy 161: I can under stand my head itself to be ‘a nut,’ — let me hope with a sound kernel, — or, to change the figure, an ‘attic,’ as being the top story of my body.
H. Alford Life (1873) 467: Tolerably well all day, but the noise in the attic unremoved.
[UK]Newcastle Courant 9 Sept. 6/5: Sam was an ‘out-f-the-way’ sort of fellow. His ’attic was well stored with salt’.
[US]P. MacKaye Sam Average in Mayorga (1919) 13: His top-loft leaks!
[US]T.A. Dorgan Indoor Sports 22 Jan. [synd. cartoon] Nobody home? Nobody ever rented that attic.
[US]Wood & Goddard Dict. Amer. Sl. 4: attic. Empty part of a house; hence head, upper story.
[US]W. Coburn Law Rides the Range 92: Some one had mentioned Pay Dirt. The name hung among the cobwebs of my attic.
[US] ‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.
[US]‘Hy Lit’ Hy Lit’s Unbelievable Dict. of Hip Words 10: When you are reading this book, you are copping some knowledge and storing it in your attic.
[US](con. 1916) G. Swarthout Tin Lizzie Troop (1978) 225: Only the Good Lord can help her in the attic, which is where she needs it.
[US]W. Diehl Sharky’s Machine 272: I’m not saying he’s a goddamn loony bird. He’s just uh, ... a little loose in the attic.
[US]Boogie Down Productions ‘Criminally Minded’ [lyrics] I’m not a musical maniac or b-boy fanatic / I simply made use of what was upstairs in the attic.
[US]H. Rawson Dict. of Invective (1991) 372: To say that someone is food for the squirrels, has squirrels in the attic (or in the nut), is playing with squirrels, is squirrelly, or has walnut storage disease are just different ways of saying that other person is crazy, eccentric, or stupid.

2. the vagina.

[UK]Farmer & Henley Sl. and Its Analogues.

In phrases

have a guest in the attic (v.)

1. (also have toys in the attic) to be eccentric, to be insane, to be simple, childlike.

[US]J. Sayles Union Dues (1978) 316: ‘Another one with toys in the attic,’ said Jackie to the men.
[US]S. King Different Seasons [ebook] Your dad was a loony [...] Loony’s kid, loony’s kid, your father’s got toys in the attic, kid, tough break.
R.J. Rafalko Logic for an overcast Tuesday 133: Either my name is Rumpelstiltskin or you've got toys in the attic.
A.C. Obscura Window with Minnie Moon [ebook] I’m an alcoholic addict with bipolar disorder / Got toys in the attic & I’m seeing your daughter.

2. to be drunk.

[UK]‘William Juniper’ True Drunkard’s Delight 225: Our tippler [...] has a guest in the attic.
messy attic (n.)

(US black) hair in need of dressing.

M. Hanks Da Hip Hop Heezy [Internet] messy attic n. hair in need of a ‘do’.