Green’s Dictionary of Slang

kadi n.

a hat.

1886		Sporting Times 6 Mar. 1/1: Let us chuck our Conservative kady in the air , and shout hooray.
1896		Mirror of Life 29 Aug. 3/3: [H]is kadi [...] covered a nut as bald as a billiard ball.
1897		W.T. Goodge ‘Great Aus. Slanguage’ in Baker Aus. Lang. (1945) 117: And his clothes he calls his clobber / Or his togs, but what of that / When a castor or a kady / Is the name he gives his hat!
1905		Sporting Times 27 May 1/5: You should have seen the kadi they found him; nine-and-a-half inches of real black beaver.
1919		W.H. Downing Digger Dialects 30: kadi (n.) — Hat.
1924		G. Henderson Keys to Crookdom 402: Dicer. Derby hat, katy.
1924		(con. WWI) A.G. Pretty Gloss. of Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: kadi. Hat.
1927		C. Samolar ‘Argot of the Vagabond’ in AS II:9 389: Katy (hat) is not strictly of the road.
1930		(con. 1910–20s) D. Mackenzie Hell’s Kitchen 119: Kadie ... hat.
1931		J.T. Farrell ‘Merry Clouters’ in Fellow Countrymen (1937) 395: A straw katy with a red-and-blue band.
1935		Chicago World 15 June 7/7: Earl Morris, with a new straw-kide [...] and white buck oxfords.
1938		D. Runyon ‘What, No Butler?’ in Runyon on Broadway (1954) 389: When Mr. Justin Veezee leaves the Club Soudan [...] he calls for his kady.
1941		Baker N.Z. Sl. 55: Other terms which probably hailed from the country are [...] cady or kadi, a straw hat.
1953		S. Bellow Augie March (1996) 20: Scythian hair stroked down under a straw katie.