slacker (n.)Related entries & more
popularized 1994, but the meaning "person who shirks work" dates to 1897; agent noun from slack (v.). In early use also slackster (1901). Compare Old English sleacornes "laziness," which is not, however, an agent noun. Related: Slackerly; slackerish.
slack (v.)Related entries & more
1510s, "to moderate, make slack," back-formed from slack (adj.) after the original verb veered into the specialized sense of slake. Meaning "be remiss, inactive or idle, fail to exert oneself" is attested from 1540s; current use is probably a re-coining from c. 1904 (see slacker, and compare Old English slacful "lazy," sleacmodnes "laziness"). Related: Slacked; slacking.