Source : Webster's Revised Unabridged Dictionary (1913)

Suspicious \Sus*pi"cious\, a. [OE. suspecious; cf. L.
   suspiciosus. See {Suspicion}.]
   1. Inclined to suspect; given or prone to suspicion; apt to
      imagine without proof.

            Nature itself, after it has done an injury, will
            ever be suspicious; and no man can love the person
            he suspects.                          --South.

            Many mischievous insects are daily at work to make
            men of merit suspicious of each other. --Pope.

   2. Indicating suspicion, mistrust, or fear.

            We have a suspicious, fearful, constrained
            countenance.                          --Swift.

   3. Liable to suspicion; adapted to raise suspicion; giving
      reason to imagine ill; questionable; as, an author of
      suspicious innovations; suspicious circumstances.

            I spy a black, suspicious, threatening could.
                                                  --Shak.

   Syn: Jealous; distrustful; mistrustful; doubtful;
        questionable. See {Jealous}. -- {Sus*pi"cious*ly}, adv.
        -- {Sus*pi"cious*ness}, n.

Source : WordNet®

suspiciousness
     n : being of a suspicious nature; "his suspiciousness destroyed
         his marriage" [syn: {suspicion}]