To police, or to patrol like a policeman. Back formation from constabulary and constable (Police station and policeman, in Great Britain)
The Wire, S01E07:

Omar said 'lf l was hunting Mr Bird, l would consider
the best package to be the red Dilly that's over there in Carrollton. That's if l happened to be *constabulating* like y'all.'

(Constabulating = continuous form of constabulate, an intransitive, dynamic verb)
by Constabulator November 20, 2010
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