Jankrow is a british term, maybe with Jamaican origins referring to a cowardly or homosexual male. The grime artist Klashnekoff often refers to 'Jankow-men'; which has the same connotations as Jankrow and 'Jankrow street' which actually means an urban area.
Joe: Hey look blood, its that Martin pussyole on Balmer Street. That boy's gonna get shanked big time ennit.
Dave: For real. That boys a Jankrow ennit.
Joe: Skeen? For real? Martin's a chi chi man? Thats sick man, I've heard he got caught beating a man off in Saino's