Green’s Dictionary of Slang

1. to have sexual intercourse; thus kifering n., an act of sexual intercourse.

c.1889		E. Field ‘Bangin’ on the Rhine’ verse 3: O, many a widow had he kifed, when Harry Smith and he / Were on the turf together in the country of the free.
1925		E. Field ‘A French Crisis’ in Facetiae Americana 19: Rasp, roger, diddle, bugger, screw, canoodle, kife and mow.
1977		D. Powis Signs of Crime 190: Kifering Act of sexual intercourse, sometimes specifically an act of adultery.

2. (US) to cheat or to steal.

1931		in Amer. Mercury Nov. 353: Circus Words [...] Kife, v. – To swindle the suckers [HDAS].
1950		Goldin et al. DAUL 117/1: Kife, v. 1. To swindle; to rob. [...] 2. To deal with unjustly.
1989		J. Morton Lowspeak.
2005		Urban Dict. 🌐 kife. To steal, pilfer, or otherwise take what is not yours. ‘Dude, I kifed a cheese bowl from Red Lobster.’.