Green’s Dictionary of Slang

in cribbage, the knave of trumps.

1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1888		N&Q Ser. 7 28 Apr. 340: The old name of cribbage was ‘noddy.’ ‘Noddy,’ being the name for the knave, has been contracted into nob .
1895		C. Crowe Aus. Sl. Dict. 53: Nob, [...] the knave of trumps in cribbage.