Green’s Dictionary of Slang

1. a thief.

1808		Jamieson’s Scot. Dict. n.p.: Nabber, a pilferer, a thief .
1937–84		Partridge DSUE (1984) 774/2: —1808.
1961		R. Gover One Hundred Dollar Misunderstanding 38: You cottinpickin crab nabber.

2. a bailiff, a constable.

1810		Splendid Follies III 118: Oxford, where [...] he might elude the pursuit of nabbers till daddy’s heart relented [OED].
1849		Glasgow Wkly Times (MO) 19 July 1/7: As for doing what you like, there is no such thing [...] No — the nabbers must have you.
1851		Manchester Spy (NH) 4 Oct. n.p.: You can’t clear out [...] The nabbers must have you.

3. (US) a police officer.

1939		Pittsburgh Courier (PA) 14 Oct. 11/1: Jimmie [...] called in the nabbers to get his money back .
1941		Pittsburgh Courier (PA) 22 Feb. 7/1: The nabbers didn’t go there with the patrol car for a chicken dinner.
c.1951		N. Algren ‘Watch Out for Daddy’ in Entrapment (2009) 122: All daddy had to do then was [...] hand the nabber left alone with us one of the Cs and flush the tea down the toilet.
1953		L. Durst Jives of Dr. Hepcat (1989) 9: Chappie you lay dead here we are going inside and make with some African golf and if the nabbers are in existence come on with the shout ‘Cool off the nabbers are about’.
1965		B. Jackson Get Your Ass in the Water (1974) 141: A Californian nabber took me, white slavery was my charge.