WordNet (r) 3.0 (2006):

ease off
    v 1: become less intense [syn: ease up, ease off, slacken
         off, flag]
    2: 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:

102 Moby Thesaurus words for "ease off":
   abate, arrest, avert, backpedal, backwater, bate, bear off, brake,
   check, clip the wings, curb, decelerate, delay, detain, die down,
   diffuse, disjoin, disperse, draw aside, draw rein, ease, ease up,
   ebb, edge off, fall, fly off, free, gee, glance, glance off,
   go off, haw, head off, hold back, hold in check, hold up, impede,
   jib, keep back, lax, let down, let go, let up, let up on, loose,
   loosen, loosen up, lose ground, lose momentum, lose speed,
   make way for, mitigate, moderate, move aside, obstruct, reef,
   rein in, relax, relent, remit, retard, scatter, set back,
   sheer off, shove aside, shunt, shy, shy off, side, sidestep,
   sidetrack, sidle, slack, slack off, slack up, slacken, slake, slow,
   slow down, slow up, stay, steer clear of, step aside, subside,
   switch, take in sail, throttle down, turn aside, turn away,
   turn back, unbend, unbrace, unglue, unlax, unleash, unstick,
   unstrain, unstring, untighten, unwind, veer off, wane