3. [syn: insidious, pernicious, subtle]
The Collaborative International Dictionary of English v.0.48:
Insidious \In*sid"i*ous\, a. [L. insidiosus, fr. insidiae an
ambush, fr. insidere to sit in; pref. in- + sedere to sit:
cf. F. insidieux. See Sit.]
1. Lying in wait; watching an opportunity to insnare or
entrap; deceitful; sly; treacherous; -- said of persons;
as, the insidious foe. "The insidious witch." --Cowper.
2. Intended to entrap; characterized by treachery and deceit;
as, insidious arts.
The insidious whisper of the bad angel. --Hawthorne.
3. Acting or proceeding unobserved or in a seemingly harmless
manner, but slowly or eventually doing great damage; as,
an insidious disease; an insidious plot.
Insidious disease (Med.), a disease existing, without
marked symptoms, but ready to become active upon some
slight occasion; a disease not appearing to be as bad as
it really is.
Syn: Crafty; wily; artful; sly; designing; guileful;
circumventive; treacherous; deceitful; deceptive. --
In*sid"i*ous*ly, adv. -- In*sid"i*ous*ness, n.
WordNet (r) 3.0 (2006):
adj 1: beguiling but harmful; "insidious pleasures"
2: intended to entrap
3: working or spreading in a hidden and usually injurious way;
"glaucoma is an insidious disease"; "a subtle poison" [syn:
insidious, pernicious, subtle]
Moby Thesaurus II by Grady Ward, 1.0:
106 Moby Thesaurus words for "insidious":
Byzantine, Machiavellian, Machiavellic, acute, amoral, arch,
artful, astute, cagey, calculating, canny, chiseling, clever,
collusive, conscienceless, corrupt, corrupted, covinous, crafty,
criminal, crooked, cunning, cute, dangerous, dark, deceitful, deep,
deep-laid, designing, devious, diplomatic, dishonest, dishonorable,
doubtful, dubious, evasive, false, falsehearted, feline, felonious,
finagling, fishy, foxy, fraudulent, furtive, gradual, guileful,
ill-got, ill-gotten, immoral, indirect, ingenious, inventive,
knowing, not kosher, pawky, perfidious, perilous, politic,
questionable, ready, resourceful, rotten, scheming, serpentine,
shady, shameless, sharp, shifty, shrewd, sinister, slick, slippery,
sly, smooth, snaky, sneaky, sophistical, stealthy, strategic,
subtile, subtle, supple, surreptitious, suspicious, tactical,
treacherous, trickish, tricksy, tricky, two-faced, unconscienced,
unconscientious, unconscionable, underhand, underhanded, unethical,
unprincipled, unsavory, unscrupulous, unstraightforward, vulpine,
wary, wily, without remorse, without shame