insidious

adj.

1. Working or spreading harmfully in a subtle or stealthy manner: insidious rumors; an insidious disease.
2. Intended to entrap; treacherous: insidious misinformation.
3. Beguiling but harmful; alluring: insidious pleasures.

[From Latin īnsidiōsus, from īnsidiae, ambush, from īnsidēre, to sit upon, lie in wait for : in-, in, on; see in-² + sedēre, to sit.]

insidiously in·sid'i·ous·ly adv.
insidiousness in·sid'i·ous·ness n.

adj

Definition: sneaky, tricky
Antonyms: fair, honest, open, sincere, straightforward

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(insid'ē-us)
adj

Coming on in a stealthy manner, in reference to the onset of a disease state.

Coming on stealthily; a gradual and subtle development.

IN BRIEF: Working ill by slow and stealthy means.

But there's another type of poison perhaps a little more insidious — thought poison — commonly called "gossip." — David. J. Schwartz, American professor, expert on motivation.

Common misspelling(s) of insidious

• ecidious

Dansk (Danish)
adj. - lumsk, snigende

Nederlands (Dutch)
sluw, bedrieglijk, verraderlijk

Français (French)
adj. - insidieux, captieux, spécieux

Deutsch (German)
adj. - heimtückisch

Ελληνική (Greek)
adj. - δόλιος, ύπουλος

Italiano (Italian)
insidioso

Português (Portuguese)
adj. - traiçoeiro

Русский (Russian)
вероломный

Español (Spanish)
adj. - insidioso, pernicioso, maligno

Svenska (Swedish)
adj. - försåtlig, lömsk, smygande

中文（简体）(Chinese (Simplified))
隐伏的, 狡猾的, 阴险的

中文（繁體）(Chinese (Traditional))
adj. - 隱伏的, 狡猾的, 陰險的

한국어 (Korean)
adj. - 흉계의, 교활한, (병 등이) 잠행성의

日本語 (Japanese)
adj. - こっそり行われる, 陰険な, 知らない間に進む

العربيه (Arabic)
‏(صفه) منتشر بالتدريج, مغوي, غادر‏

עברית (Hebrew)
adj. - ‮חתרני, פועל מתחת לפני השטח, הרסני בחשאי, חורש מזימות, ערמומי, מתעה‬

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