1813, "to thrust or strike with a point," a Scottish variant of job "to strike, pierce, thrust," from Middle English jobben "to jab, thrust, peck" (c. 1500), a word of unknown origin, perhaps imitative. Related: Jabbed; jabbing.
1825, "a thrust or poke with the point of something," from jab (v.). Meaning "a punch with the fist" is from 1889. Sense of "injection with a hypodermic needle," once beloved by newspaper headline writers, is from 1914.