WordNet (r) 3.0 (2006):

ease up
    v 1: move in order to make room for someone for something; "The
         park gave way to a supermarket"; "`Move over,' he told the
         crowd" [syn: move over, give way, give, ease up,
         yield]
    2: become less intense [syn: ease up, ease off, slacken
       off, flag]
    3: reduce pressure or intensity; "he eased off the gas pedal and
       the car slowed down" [syn: ease up, ease off, let up]

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "ease up":
   abate, arrest, backpedal, backwater, bate, brake, check,
   clip the wings, curb, decelerate, delay, detain, draw rein, ease,
   ease off, hold back, hold in check, hold up, impede, keep back,
   let down, let up, let up on, loose, loosen, lose ground,
   lose momentum, lose speed, mitigate, moderate, obstruct, reef,
   rein in, relax, remit, retard, set back, slack, slack off,
   slack up, slacken, slake, slow, slow down, slow up, stay,
   take in sail, throttle down, unbend, unbrace, unlax, unstrain,
   unstring, unwind