1. [n]  a cord or rope or cable that is hanging loosely; "he took of the slack"
2. [n]  the condition of being loose (not taut); "he hadn't counted on the slackness of the rope"
3. [n]  a stretch of water without current or movement; "suddenly they were in slack water"
4. [n]  a noticeable decline in performance; "the team went into a slump"; "a sudden slack in output"; "a drop-off in attendance"; "a falloff in automobile sales"
5. [adj]  lacking in rigor or strictness; "such lax and slipshod ways are no longer acceptable"; "lax in attending classes"; "slack in maintaining discipline"
6. [adj]  flowing with little speed as e.g. at the turning of the tide; "slack water"
7. [adj]  lacking in strength or firmness or resilience; "flaccid muscles"; "took his lax hand in hers"; "gave a limp handshake"; "a limp gesture as if waving away all desire to know" G.K.Chesterton; "a slack grip"
8. [adj]  not tense or taut; "the old man's skin hung loose and gray"; "slack and wrinkled skin"; "slack sails"; "a slack rope"
9. [v]  cause to heat and crumble by treatment with water, as of lime
10. [v]  become less in amount or intensity; "The storm abated"
11. [v]  make less active or intense
12. [v]  become slow or slower; "Production slowed"
13. [v]  make less active or fast; "He slackened his pace as he got tired"; "Don't relax your efforts now"
14. [v]  release tension on; "slack the rope"
15. [v]  be inattentive to, or neglect, as of duties; "He slacks his attention"
16. [v]  avoid responsibilities and work, be idle

Slack
Breathing space is crucial if efficiency efforts are to succeed; in other words, cut your employees some slack. That`s the heart of consultant DeMarco`s book on improving a company`s verve and production. SLACK provides some basic diagnostic evaluations and exercises executives can employ in order to establish the wiggle room necessary to thrive amid change and pressure.

more details ...

1. \Slack\, n. [Cf. {Slag}.]
   Small coal; also, coal dust; culm. --Raymond.
   

2. \Slack\, n. [Icel. slakki a slope on a mountain edge.]
   A valley, or small, shallow dell. [Prov. Eng.] --Grose.
   

3. \Slack\, a. [Compar. {Slacker}; superl. {Slackest}.] [OE.
   slak, AS. sleac; akin to OS. slak, OHG. slah, Prov. G.
   schlack, Icel. slakr, Sw. slak; cf. Skr. s[.r]j to let loose,
   to throw. Cf. {Slake}.]
   Lax; not tense; not hard drawn; not firmly extended; as, a
   slack rope.
   2. Weak; not holding fast; as, a slack hand. --Milton.
   3. Remiss; backward; not using due diligence or care; not
      earnest or eager; as, slack in duty or service.
            The Lord is not slack concerning his promise, as
            some men count slackness.             --2 Pet. iii.
                                                  9.
   4. Not violent, rapid, or pressing; slow; moderate; easy; as,
      business is slack. ``With slack pace.'' --Chaucer.
            C?sar . . . about sunset, hoisting sail with a slack
            southwest, at midnight was becalmed.  --Milton.
   {Slack in stays} (Naut.), slow in going about, as a ship.
   {Slack water}, the time when the tide runs slowly, or the
      water is at rest; or the interval between the flux and
      reflux of the tide.
   {Slack-water navigation}, navigation in a stream the depth of
      which has been increased, and the current diminished, by a
      dam or dams.
   Syn: Loose; relaxed; weak; remiss; backward; abated;
        diminished; inactive; slow; tardy; dull.
   

4. \Slack\, adv.
   Slackly; as, slack dried hops.
   

5. \Slack\, n.
   The part of anything that hangs loose, having no strain upon
   it; as, the slack of a rope or of a sail.
   

6. \Slack\, Slacken \Slack"en\, v. i. [imp. & p. p.
   {Slacked}, {Slackened}; p. pr. & vb. n. {Slacking},
   {Slackening}.] [See {Slack}, a.]
   1. To become slack; to be made less tense, firm, or rigid; to
      decrease in tension; as, a wet cord slackens in dry
      weather.
   2. To be remiss or backward; to be negligent.
   3. To lose cohesion or solidity by a chemical combination
      with water; to slake; as, lime slacks.
   4. To abate; to become less violent.
            Whence these raging fires Will slacken, if his
            breath stir not their flames.         --Milton.
   5. To lose rapidity; to become more slow; as, a current of
      water slackens.
   6. To languish; to fail; to flag.
   7. To end; to cease; to desist; to slake. [Obs.]
            That through your death your lineage should slack.
                                                  --Chaucer.
            They will not of that firste purpose slack.
                                                  --Chaucer.
   

7. \Slack\, Slacken \Slack"en\, v. t.
   1. To render slack; to make less tense or firm; as, to slack
      a rope; to slacken a bandage. --Wycklif (Acts xxvii. 40)
   2. To neglect; to be remiss in. [Obs.] --Shak.
            Slack not the pressage.               --Dryden.
   3. To deprive of cohesion by combining chemically with water;
      to slake; as, to slack lime.
   4. To cause to become less eager; to repress; to make slow or
      less rapid; to retard; as, to slacken pursuit; to slacken
      industry. ``Rancor for to slack.'' --Chaucer.
            I should be grieved, young prince, to think my
            presence Unbent your thoughts, and slackened 'em to
            arms.                                 --Addison.
            In this business of growing rich, poor men should
            slack their pace.                     --South.
            With such delay Well plased, they slack their
            course.                               --Milton.
   5. To cause to become less intense; to mitigate; to abate; to
      ease.
            To respite, or deceive, or slack thy pain Of this
            ill mansion.                          --Milton.
   {Air-slacked lime}, lime slacked by exposure to the air, in
      consequence of the absorption of carton dioxide and water,
      by which it is converted into carbonate of lime and
      hydrate of lime.
   

1. Internal fragmentation. Space allocated to a disk file but not actually used to store useful information.

2. In the theology of the Church of the SubGenius, a mystical substance or quality that is the prerequisite of all human happiness.

Since Unix files are stored compactly, except for the unavoidable wastage in the last block or fragment, it might be said that "Unix has no slack".

See ha ha only serious.

[Jargon File]