- slack (n.)
- "coal dust," c.1440, sleck, probably from M.Du. slacke, M.L.G. slecke "slag, small pieces left after coal is screened," perhaps related to slagge "splinter flying off metal when it is struck" (see slag).
- slack (adj.)
- O.E. slęc "loose, careless" (in ref. to personal conduct), from P.Gmc. *slakas (cf. O.S. slak, O.N. slakr, O.H.G. slah "slack," M.Du. lac "fault, lack"), from PIE base *(s)leg- "to be slack" (see lax). Sense of "not tight" (in ref. to things) is first recorded c.1300. The verb is attested from 1520; slacken (v.) first recorded 1580. Slack-key (1975) translates Hawaiian ki ho'alu First record of slack-jawed (1901) is in Kipling. Slack water "time when tide is not flowing" is from 1769. Slacker popularized 1994, though meaning "person who shirks work" dates back to 1898.
- slack (n.)
- 1794, "loose part or end" (of a rope, sail, etc.), from slack (adj.); hense fig. senses in take up the slack (1930) and slang cut (someone) some slack (1968). Meaning "quiet period, lull" is from 1851. Slacks "loose trousers" first recorded 1824, originally military.