Green’s Dictionary of Slang

I and I n.

also Iyah Nyah
[I and I pron.]

(W.I. Rasta/UK black teen) a Rastafarian; usu. attrib.

[WI]S. Baku ‘Revo’ in Three Plays (1984) II i: No I and I business! Cigar is a lift! Destabilisation is a spliff!
[WI]M. Montague Dread Culture 15: Iyah Nyah looked at him and smiled.
[UK]K. Richards Life 344: What really turned me on [about Rastafarianism] is there’s no you and I, there’s just I and I.