The Collaborative International Dictionary of English v.0.48:

Shudder \Shud"der\, v. i. [imp. & p. p. Shuddered;p. pr. & vb.
   n. Shuddering.] [OE. shoderen, schuderen; akin to LG.
   schuddern, D. schudden to shake, OS. skuddian, G. schaudern
   to shudder, sch["u]tteln to shake, sch["u]tten to pour, to
   shed, OHG. scutten, scuten, to shake.]
   To tremble or shake with fear, horrer, or aversion; to shiver
   with cold; to quake. "With shuddering horror pale." --Milton.
   [1913 Webster]

         The shuddering tennant of the frigid zone. --Goldsmith.
   [1913 Webster]

WordNet (r) 3.0 (2006):

shuddering
    adj 1: shaking convulsively or violently

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "shuddering":
   abhorrence, abomination, ague, allergy, antagonism, antipathy,
   aspen, aversion, bumpiness, chattering, chorea, cold shivers,
   cold sweat, creeping flesh, disgust, enmity, fits and starts, hate,
   hatred, horror, hostility, jactation, jactitation, jerkiness,
   joltiness, loathing, mortal horror, nausea, palsied, palsy,
   quaking, quavering, quavery, quivering, quivery, repugnance,
   repulsion, shakes, shaking, shaky, shivering, shivers, shivery,
   spasms, succussatory, succussion, succussive, trembling, trembly,
   tremulous, tremulousness, vibrating, vibration, wobbly