See slack in Webster's New World Roget's A-Z Thesaurus II
adjective
Characterized by reduced economic activity:
down, dull, off, slow, sluggish, soft. See increaseNot tautly bound, held, or fastened:
lax, loose, relaxed. See tightenGuilty of neglect; lacking due care or concern:
derelict, lax, neglectful, negligent, remiss. See careful
verb
To reduce in tension, pressure, or rigidity:
ease, let up, loose, loosen, relax, slacken, untighten. See tightenTo avoid the fulfillment of:
disregard, neglect, shirk. Idiom: let slide. See do
phrasal verb slack offTo become or cause to become less active or intense:
abate, bate, die (away, down, off, or out), ease (off or up), ebb, fall, fall off, lapse, let up, moderate, remit, slacken, subside, wane. See increase
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