2. Lacking in activity; not busy: a slack season for the travel business.
3. Not tense or taut; loose: a slack rope; slack muscles. See Synonyms at loose.
4. Lacking firmness; flaccid: a slack grip.
5. Lacking in diligence or due care or concern; negligent: a slack worker. See Synonyms at negligent.
6. Flowing or blowing with little speed: a slack current; slack winds.
7. Linguistics Pronounced with the muscles of the tongue and jaw relatively relaxed; lax.
v.slacked, slack·ing, slacks
v.tr.
1. To make slower or looser; slacken.
2. To be careless or remiss in doing: slack ones duty.
3. To slake (lime).
v.intr.
1. To be or become slack.
2. To evade work; shirk.
n.
1. A loose part, as of a rope or sail.
2. A lack of tension; looseness.
3. A period of little activity; a lull.
4.
a. A cessation of movement in a current of air or water.
b. An area of still water.
5. Unused capacity: still some slack in the economy.
6. slacks Casual trousers that are not part of a suit.
adv.
In a slack manner: a banner hanging slack.
Phrasal Verb:
slack off
To decrease in activity or intensity.
Idiom:
cut/give(someone) some slack
Slang To make an allowance for (someone), as in allowing more time to finish something.
[Middle English slak, from Old English slæc; see slg- in Indo-European roots.]
slackly adv.
slackness n.
slack 2(slk)
n.
A mixture of coal fragments, coal dust, and dirt that remains after screening coal.
[Middle English sleck.]
slack 3(slk)
n.Chiefly British
1. A small dell or hollow.
2. A bog; a morass.
[Middle English slak, from Old Norse slakki.]
slack /slk/ n. [U] 1 lack of tightness, looseness in s.t., such as a string, fish line, or rope: There is some slack in this rope, so you can pull it tighter.2 infrml.to cut or give s.o. some slack: to give s.o. the right to be wrong, to give s.o. more of a chance: Youre too strict with your son; cut him some slack.-n. [U] slackness. adj.1 not tight or firm: a slack wire2 not working hard, not busy, lazy: The boss told the slack worker to take fewer coffee breaks. v. [I] to slack off: to be less active, slow down: The rain is slacking off; lets go outside.||This job is almost done; lets slack off for a while.See: slacken.
k/ n. [U] 1 lack of tightness, looseness in s.t., such as a string, fish line, or rope: There is some slack in this rope, so you can pull it tighter. 2 infrml. to cut or give s.o. some slack: to give s.o. the right to be wrong, to give s.o. more of a chance: Youre too strict with your son; cut him some slack. -n. [U] slackness.
adj. 1 not tight or firm: a slack wire 2 not working hard, not busy, lazy: The boss told the slack worker to take fewer coffee breaks. 
k)
g- in Indo-European roots.]
ly adv.