Green’s Dictionary of Slang

1. (also zingie) something exceptional, whether good or bad.

1950		Goldin et al. DAUL 244/1: Zingers, or zinger. 1. Any powerful influence capable of decisively affecting the legal disposition of a criminal case whether favorably or adversely.
1953		W. Brown Monkey On My Back (1954) 241: Pepe promised to [...] take me to a night club where the strippers were ‘zingies.’.
1970		Time 30 Nov. 32: A stunning blonde zinger from North Carolina.
1997		C. Hiaasen Lucky You 300: The managing editor would have loved to use that line (and a dozen other zingers) in his tribute.

2. a witty line, a one-line joke or repartee; a slanderous or disparaging comment.

1950		Goldin et al. DAUL 244/1: Zingers, or zinger. [...] 2. Scandal or slander deliberately disseminated [...] 3. Any deliberately disparaging, personal remark.
1960		H. Ellison ‘Final Shtick’ in Gentleman Junkie (1961) 16: Oooh, that was a zinger, wasn’t it, Marty.
1971		Time 7 June 32: No sooner did Cavett sit down than he tossed a zinger.
1986		S. King It (1987) 303: When referring to verbal zingers and loud farts, Richie’s terminology was the same.
1994		N. McCall Makes Me Wanna Holler (1995) 116: He [...] threw out a zinger without missing a beat.
2000		Guardian 7 Feb. 19: Stewart Laing’s exuberant revival sacrifices too many of West’s zingers to backstage atmosphere.
2011		Independent 5 Oct. 7/3: Even George Osborne [...] came close to a zinger [...] with a gag about Eric Pickles’ personal trainer.
2017		Lincon Jrnl Star (NE) 25 Feb. D5/5: My daughter is the recipient of at least one insult per visit [...] these zingers being hurled on a regular basis.

3. a surprise question, an unexpected turn of events.

1967		J. Olsen Black is Best 241: [T]he American public is so desirous of lancing this boil on their rear end that they just might lance him [i.e. Muhammad Ali] right out of the decision. They may give him the old zinger, boxing-style.
1973		R. Thomas If You Can’t Be Good (1974) 51: I would drone along [...] asking tired questions [...] Then I would throw in the zinger and watch what happened [OED].
2012		J. Díaz This Is How You Lose Her 97: My brother had never been the most rational of agents but this one was the ill zinger.