Suspicious, a.
Etymology: [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.
Shades of meaning
Fernald has no entry of its own for suspicious; he lists it under envious, equivocal.
Where he writes about it:
One is suspicious of another from unfavorable indications or from a knowledge of wrong in his previous conduct, or even without reason. — from envious
A suspicious character gives manifest reason to be suspected; a suspicious temper is inclined to suspect the motives and intentions of others, with or without reason. — from equivocal