WordNet (r) 3.0 (2006):

brace up
    v 1: make secure underneath; "undergird the ship" [syn:
         undergird, brace up]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "brace up":
   animate, assure, beef up, bolster, brace, brighten up, brisk,
   brisken, buck up, buttress, case harden, cheer, cheer up, chirk up,
   confirm, convalesce, embolden, encourage, enliven, exhilarate,
   fortify, fresh up, freshen, freshen up, gain strength, get better,
   gird, harden, hearten, improve, inspire, inspirit, invigorate,
   light up, nerve, perk up, pick up, prop, quicken, rally, reanimate,
   reassure, recreate, recruit, recuperate, refresh, refreshen,
   regale, reinforce, reinvigorate, renew, restrengthen, revive,
   revivify, set up, shore up, sleep it off, steel, stiffen,
   stimulate, strengthen, support, sustain, take courage, take heart,
   temper, toughen, turn the corner, undergird, vivify