slacken

1 to make less taut <you'll need to slacken the rope a bit to get it free of that post> Synonyms ease, loosen, relax, slack Related Words detach, free, unbind, undo, unfasten, untie Near Antonyms attach, bind, fasten, tie; constrain, restrain Antonyms strain, stretch, tense, tension, tighten

2 to cause to move or proceed at a less rapid pace <drivers need to slacken their speed as they approach the sharp curve> Synonyms brake, decelerate, retard, slowRelated Words halt, stop; encumber, hamper, handicap, hinder, hobble, hold back, hold up, impede, inhibit, obstruct, set back, tie up; bottleneck; arrest, check, constrain, curb, rein, restrain; baffle, foil, frustrate, sabotage, thwartNear Antonyms drive, encourage, goad, propel, push, spur, stir, urge; advance, aid, dispatch, ease, expedite, facilitate, forward, further, helpAntonyms accelerate, hasten, hurry, quicken, rush, speed (up), step up