Green’s Dictionary of Slang

exis-evif yeneps n.

elevenpence.

1859		Hotten Dict. of Modern Sl. etc. 127: EXIS-EVIF YENEPS, elevenpence, – literally, ‘6 pence and 5 pence = elevenpence.’ This mode of reckoning, distinct from the preceding, is also common amongst those who use the back slang.
1864, 1867, 1870		Hotten Sl. Dict. [as cit. 1859].
1873		Sl. Dict.