Green’s Dictionary of Slang

tom pat n.¹

a parson.

1728		Defoe Street Robberies Considered 35: Tom Pat, a Parson.
1741		Canting Academy, or the Pedlar’s-French Dict. 114: A Parson Tom Patt.
1789		G. Parker Life’s Painter 137: pal.: What, are Moll and you adam’d? joe: Yes we are, and by a rum Tom Pat too.
a.1790		H.T. Potter New Dict. Cant (1795).
1845		G.W.M. Reynolds Mysteries of London vol. 2 142: Rum-Tom-Pat Clergyman.
1887		Cornishman 6 Jan. 4/3: Specimens of mumpers' or tramps' talk [...] tom-pat, a parson.