WordNet (r) 3.0 (2006):

beat up
    v 1: give a beating to; subject to a beating, either as a
         punishment or as an act of aggression; "Thugs beat him up
         when he walked down the street late at night"; "The teacher
         used to beat the students" [syn: beat, beat up, work
         over]
    2: gather; "drum up support" [syn: beat up, drum up,
       rally]

Moby Thesaurus II by Grady Ward, 1.0:

139 Moby Thesaurus words for "beat up":
   agitate, all in, batter, battered, beat, beat-up, beaten,
   beaten up, bedraggled, blowzy, bone-weary, broken-down, bruise,
   bushed, careless, chintzy, churn, churn up, clabber, clot,
   coagulate, colloid, colloidize, convulse, cream, curdle, dead,
   dead-and-alive, dead-tired, deadbeat, decrepit, derelict,
   dilapidated, disarrange, discompose, disquiet, disturb, dog-tired,
   dog-weary, done, done in, done up, drabbletailed, draggled,
   draggletailed, drained, emulsify, emulsionize, excite, exhausted,
   fagged out, ferment, flurry, fret, frowzy, frumpish, frumpy, gone,
   grubby, in rags, in ruins, incrassate, informal, inspissate, jell,
   jellify, jelly, knocked out, loose, lopper, lumpen, messy, mussy,
   negligent, paddle, perturb, perturbate, played out, poky, pooped,
   pooped out, prostrate, ragged, raggedy, ramshackle, ready to drop,
   rile, ripple, roil, roughen, ruffle, ruined, ruinous, rumple,
   run-down, scraggly, seedy, shabby, shake, shake up, shoddy, slack,
   slatternly, slipshod, sloppy, slovenly, slummy, sluttish, sordid,
   spent, squalid, stir, stir up, swirl, tacky, tattered, thicken,
   thrash soundly, tired out, tired to death, tottery, trouble,
   tuckered out, tumbledown, unkempt, unneat, unsightly, untidy,
   upset, used up, washed-up, weary unto death, whacked, whip,
   whip up, whisk, wiped out, work up, worn-out