Green’s Dictionary of Slang

1. a clay pipe with a very long stem.

1857		T. Hood Pen and Pencil Pictures 269: Thrust me a pair of Cutties into my girdle for pistols; hang a Churchwarden by my side for a sabre.
1863		A. Smith Dreamthorp 262: He took his seat beside us, lifted a pipe of the kind called ‘churchwarden’ from the box on the ground, filled and lighted it.
1876		J. Greenwood Low-Life Deeps 14: Not a short pipe, but a regular full-length ‘churchwarden’.
1879		Dodge City Times (KS) 8 Mar. 3/1: Tenyson is extremely fond of smoking the long clay pipe called a ‘churchwarden’.
1895		Crowe Aus. Sl. Dict. 98: Yard of Clay, a long pipe also named church-warden.
1898		Belfast News-Letter 11 Apr. 6/5: Long clay pipes have long been known as ‘churchwardens’.
1911		Byran Dly Eagle (TX) 14 June 6/5: A sailor [...] borught up from the depths a long churchwarden pipe.
1928		Derby Dly Teleg. 9 Oct. 7/1: Lady Studd [...] joined in smoking the ‘churchwarden.’ ‘I enjoyed my evening [...] Smoking is most pleasant’.

2. (US drugs) a long-stemmed pipe used to smoke cannabis or opium.

1911		W. Australian (Perth) 10 July 8/8: The pipe has many forms. The hookah and nargileh, the long ‘churchwarden’.
1935		A.J. Pollock Und. Speaks 21/2: Church warden, a long stem opium pipe of exceptional quality.