Green’s Dictionary of Slang

nosrap n.

a parson.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1882		Sydney Sl. Dict. (2 edn) 11: Nos-rap - A parson.
1933		Derby Dly Teleg. 7 Aug. 6/4: Back-slang [...] of which the costermongers of London boast [...] flatchyennep (halfpenny), nos-rap (parson), and kirb (brick).