The Collaborative International Dictionary of English v.0.48:

Suspect \Sus*pect"\, v. t. [imp. & p. p. Suspected; p. pr. &
   vb. n. Suspecting.]
   1. To imagine to exist; to have a slight or vague opinion of
      the existence of, without proof, and often upon weak
      evidence or no evidence; to mistrust; to surmise; --
      commonly used regarding something unfavorable, hurtful, or
      wrong; as, to suspect the presence of disease.
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            Nothing makes a man suspect much, more than to know
            little; and therefore men should remedy suspicion by
            procuring to know more.               --Bacon.
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            From her hand I could suspect no ill. --Milton.
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   2. To imagine to be guilty, upon slight evidence, or without
      proof; as, to suspect one of equivocation.
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   3. To hold to be uncertain; to doubt; to mistrust; to
      distruct; as, to suspect the truth of a story. --Addison.
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   4. To look up to; to respect. [Obs.]
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   Syn: To mistrust; distrust; surmise; doubt.
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Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "suspecting":
   Pyrrhonic, agnostic, cagey, cautious, chary,
   disinclined to believe, disposed to doubt, distrustful, doubtful,
   doubting, dubious, from Missouri, guarded, hard of belief,
   impervious to persuasion, in doubt, inconvincible, incredulous,
   leery, mistrustful, mistrusting, questioning, scrupulous, shy,
   shy of belief, skeptical, suspicious, uncertain, unconvincible,
   uncredulous, unpersuadable, unpersuasible, untrusting,
   unwilling to accept, wary