Synonyms and related words :
Argus-eyed, Machiavellian, Machiavellic, Pyrrhonic, Scotch, acute, agnostic, all ears, all eyes, arch, artful, astute, aux aguets, cagey, calculating, canny, careful, cautious, chary, circumspect, clever, considerate, crafty, cunning, custodial, cute, deceitful, deep, deep-laid, designing, diplomatic, discreet, disinclined to believe, disposed to doubt, distrustful, doubtful, doubting, dubious, eagle-eyed, feline, foxy, from Missouri, frugal, gingerly, guarded, guileful, hard of belief, hawk-eyed, impervious to persuasion, in doubt, inconvincible, incredulous, ingenious, insidious, inventive, keen-eyed, knowing, leery, lidless, mistrustful, mistrusting, observant, on guard, on the lookout, on the watch, open-eyed, pawky, politic, provident, prudent, questioning, ready, resourceful, safe, saving, scheming, scrupulous, serpentine, sharp, sharp-eyed, shifty, shrewd, shy, shy of belief, skeptical, sleepless, slick, slippery, sly, smooth, snaky, sneaky, sophistical, stealthy, strategic, subtile, subtle, supple, suspecting, suspicious, tactical, thrifty, trickish, tricksy, tricky, uncertain, unconvincible, uncredulous, unpersuadable, unpersuasible, untrusting, unwasteful, unwilling to accept, vigilant, vulpine, watchful, wily, with open eyes