jump outs

the officers of the law in disguise

noun. Slang term for the police, specifically the uniformed arrest teams that speed into the block, emerge quickly from their vehicles, and make arrests. Developed in the 1980s to combat inner-city narcotics distribution.

to act brave, as if one is ready for a fight

Going out with friends, off to chill, hang out, trek around

When a Hemel chav gets mad at another human and threatens to kill you

Unmarked police rolling down the Blade, four or more of them in each single large tint-windowed SUV or van with no back windows, waiting for a vice officer to confirm having positively identified a target — a prostitute, pimp, dealer, or someone with an outstanding warrant or who was banned by the courts from the area for previous prostitution or drug activity — or, after seeing such activity taking place or identifying a known suspect themselves as they go by, they roll up to the target(s), quickly stop and all jump out to arrest/search/question or otherwise harass everyone involved.

'Jump Out Boys' is a phrase used to describe police, detectives, undercover officers, and other law enforcement personel.
More specifically the term refers to officers involved in sting opereations. (Narcotics, Prostitution, Organized Crime etc.)
The 'Jump Out Boys' are usually either the swat team, or the cops on stake outs inside the sound van, listening in on wire taps or wired informants. When tipped off, or alerted, these officers are known to jump out of the vehicle and subdue suspects by force, thus the term 'Jump Out Boys'.
They ride in unmarked vehicles, typically vans, trucks, and vehicles without windows.
Some gangs and/or squads are known tocall themselves 'Jump Out Boys' due to their simmilar, jump out style.