constab, n. — Green’s Dictionary of Slang

constab n.

[abbr.; note dial. constab tick, a cattle tick – its stripes resemble those on the constable’s trousers; also constab-macka, a large prickle]

(W.I.) a police officer, a constable.

1907		in W. Jekyll Jam. Song and Story 205: Drill him, Constab, drill him; She tief her mother shilling [...] Wheel him, Constab, wheel him.
1912		C. McKay ‘Disillusioned’ Constab Ballads 44: Foolish, foolish young gals who / T’ink a constab could be true!