WordNet (r) 3.0 (2006):

hold fast
    v 1: stick to firmly; "Will this wallpaper adhere to the wall?"
         [syn: adhere, hold fast, bond, bind, stick,
         stick to]

Moby Thesaurus II by Grady Ward, 1.0:

108 Moby Thesaurus words for "hold fast":
   adhere to, arrest, be unflappable, bear up, bite, bridle, check,
   clasp, cleave to, clench, clinch, cling, cling like ivy, clip,
   clutch, come up fighting, constrain, contain, control, cool,
   cool off, curb, curtail, decelerate, dig in, dompt, embrace,
   enjoin, freeze to, get home free, govern, grapple, grasp, grip,
   gripe, guard, hang in, hang in there, hang on, hang on to,
   hang tough, hinder, hold, hold at bay, hold back, hold in,
   hold in check, hold in leash, hold on, hold on to, hold out,
   hold tight, hold up, hug, inhibit, keep, keep back, keep from,
   keep hold of, keep in, keep in check, keep under control,
   lay under restraint, live through it, live with it, never let go,
   never say die, nip, not budge, not give up, prohibit, pull,
   pull in, rein, rein in, remain firm, restrain, retard, retrench,
   ride it out, set back, slow down, snub, stand fast, stand firm,
   stand no nonsense, stand pat, stand the gaff, stand up,
   stay it out, stay put, stay the distance, stay with it, stick,
   stick close, stick fast, stick it, stick it out, stick out,
   stick to, stick to it, stick with it, straiten, take what comes,
   tough it out, weather, weather the storm, withhold