Green’s Dictionary of Slang

attic n.

1. [early 19C+] (orig. boxing, also top-loft) the head.

2. [late 19C] the vagina.

In phrases

have a guest in the attic (v.) [20C+]

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

2. to be drunk.

messy attic (n.)

[1950s+] (US black) hair in need of dressing.