The Collaborative International Dictionary of English v.0.48:

Throb \Throb\, v. i. [imp. & p. p. Throbbed; p. pr. & vb. n.
   Throbbing.] [OE. [thorn]robben; of uncertain origin; cf.
   Russ. trepete a trembling, and E. trepidation.]
   To beat, or pulsate, with more than usual force or rapidity;
   to beat in consequence of agitation; to palpitate; -- said of
   the heart, pulse, etc.
   [1913 Webster]

         My heart
         Throbs to know one thing.                --Shak.
   [1913 Webster]

         Here may his head lie on my throbbing breast. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Throb \Throb\, n.
   A beat, or strong pulsation, as of the heart and arteries; a
   violent beating; a papitation:
   [1913 Webster]

         The impatient throbs and longings of a soul
         That pants and reaches after distant good. --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

throb
    n 1: a deep pulsating type of pain
    2: an instance of rapid strong pulsation (of the heart); "he
       felt a throbbing in his head" [syn: throb, throbbing,
       pounding]
    v 1: pulsate or pound with abnormal force; "my head is
         throbbing"; "Her heart was throbbing"
    2: expand and contract rhythmically; beat rhythmically; "The
       baby's heart was pulsating again after the surgeon massaged
       it" [syn: pulsate, throb, pulse]
    3: tremble convulsively, as from fear or excitement [syn:
       shudder, shiver, throb, thrill]

Moby Thesaurus II by Grady Ward, 1.0:

143 Moby Thesaurus words for "throb":
   ache, agonize, ail, anguish, arrhythmia, bar beat, barrage, beat,
   beat a ruffle, beat a tattoo, beating, bicker, blanch, blench,
   dance, didder, disquiet, disquietude, dithers, downbeat, drum,
   drum music, drumbeat, drumfire, drumming, feel pain,
   feel the pangs, fidget, fidgetiness, fidgets, flap, flick, flicker,
   flip, flip out, flit, flitter, flop, flutter, freak out on,
   get high on, glow, go pitapat, grimace, gutter, have a misery,
   have the fidgets, have the shakes, heartbeat, heartthrob, heave,
   heaving, hurt, inquietude, jerk, offbeat, palpitate, palpitation,
   pant, panting, paradiddle, patter, pitapat, pitter-patter, pound,
   pounding, pulsate, pulsation, pulse, quake, quaking, quaver,
   quavering, quiver, quivering, rat-a-tat, rat-tat, rat-tat-tat,
   rataplan, rattattoo, resonate, restlessness, rhythm, roll,
   rub-a-dub, ruff, ruffle, shake, shakes, shaking, shiver, shivers,
   shoot, shrink, shudder, slat, smart, sound a tattoo, spatter,
   splatter, splutter, sputter, squirm, staccato, suffer, swell,
   swell with emotion, tat-tat, tattoo, tempo, thrill, thrill to,
   throbbing, thrum, thump, thumping, tick, ticktock, tingle,
   tingle with excitement, tom-tom, toss, toss and turn, tremble,
   trembling, tremor, trepidation, trepidity, tumble, turn on to,
   twinge, twist and turn, twitch, twitter, unrest, upbeat, vibrate,
   wave, waver, wiggle, wince, wriggle, writhe