The Collaborative International Dictionary of English v.0.48:

Stagger \Stag"ger\ (-g[~e]r), v. i. [imp. & p. p. Staggered
   (-g[~e]rd); p. pr. & vb. n. Staggering.] [OE. stakeren,
   Icel. stakra to push, to stagger, fr. staka to punt, push,
   stagger; cf. OD. staggeren to stagger. Cf. Stake, n.]
   1. To move to one side and the other, as if about to fall, in
      standing or walking; not to stand or walk with steadiness;
      to sway; to reel or totter.
      [1913 Webster]

            Deep was the wound; he staggered with the blow.
                                                  --Dryden.
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   2. To cease to stand firm; to begin to give way; to fail.
      "The enemy staggers." --Addison.
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   3. To begin to doubt and waver in purpose; to become less
      confident or determined; to hesitate.
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            He [Abraham] staggered not at the promise of God
            through unbelief.                     --Rom. iv. 20.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "staggered":
   agape, aghast, agog, all agog, amazed, astonished, astounded,
   at gaze, awed, awestruck, beguiled, bendy, bewildered, bewitched,
   bowled down, breathless, captivated, chevronwise, chevrony,
   confounded, crankled, crooked, curvy, dumbfounded, dumbstruck,
   electrified, enchanted, enraptured, enravished, enthralled,
   entranced, fascinated, flabbergasted, flexuous, gaping, gauping,
   gazing, hairpin, hypnotized, in awe, in awe of, jarred, jolted,
   lost in wonder, marveling, mesmerized, open-eyed, openmouthed,
   overwhelmed, popeyed, puzzled, rapt in wonder, shaken, shocked,
   shook, spellbound, staring, startled, stupefied, surprised,
   taken aback, thunderstruck, twisty, under a charm, wide-eyed,
   wonder-struck, wondering, zigzag, zigzaggy, zigzagways