Green’s Dictionary of Slang

1. a poker.

1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc.
1835		‘Billy Bighead’ in Cove in Spedding & Watt (eds) Bawdy Songbooks (2011) IV 227: His cannister [was] crack’d with a kennedy.
1852		Bell’s Life in Sydney 23 Oct. 3/2: The man who ‘struck Buckley wid a Kinnidy’.
1864		Athenaeum 29 Oct. 559: St. Giles’s perpetuates the memory of a... man... who was killed by a poker by calling that instrument a kennedy [F&H].
1870		Hotten Sl. Dict.
1898		Binstead & Wells Pink ’Un and Pelican 208: ‘Kennedy’ Knight, the ‘Kennedy’ from his having once laid a man out with a poker after the fashion of the gent who first made the name famous by a similar exploit in St Giles’ many years ago.

2. a blow inflicted with a poker [f. a man who allegedly suffered thus in London’s St Giles slums].

1887

W.E. Henley ‘Villon’s Good-Night’ in Farmer Musa Pedestris (1896) 175: Paste ’em, and larrup ’em, and lamm! / Give Kennedy, and make ’em crawl!

3. a cosh.

1979

(con. 1920s) J. White ‘Campbell Bunk’ in History Workshop 26: A rich vein of slang which harked back to an older London street culture [...] Words which were not current in ordinary working-class speech [...] kennedy (cosh) .

4. the penis [fig. use of sense 1].

1980

Maledicta IV:2 (Winter) 191: Thus the […] the kennedy (= poker) pokes the fires of Hell, the wedge enters the crack and the placket-racket engages with the placket.