First Known Use: 1545
Dictionary
insidious
adjective in·sid·i·ous \in-ˈsi-dē-əs\
: causing harm in a way that is gradual or not easily noticed
Full Definition of INSIDIOUS
1
a : awaiting a chance to entrap : treacherous b : harmful but enticing : seductive <insidious drugs>
2
a : having a gradual and cumulative effect : subtle <the insidious pressures of modern life> b of a disease : developing so gradually as to be well established before becoming apparent
— in·sid·i·ous·ly adverb
— in·sid·i·ous·ness noun
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Examples of INSIDIOUS
- But the litigation is also prompting a subtle and insidious change in the way that medicine is practiced, which affects anyone who consults a health professional, even if they would not dream of setting foot in a lawyer's office. It is known as “defensive medicine.” —Geoff Watts, New Scientist, 23–29 Oct. 2004
- Spin is sometimes dismissed as a simple euphemism for lying. But it's actually something more insidious: indifference to the truth. —Michael Kinsley, Time, 25 Dec. 2000–1 Jan. 2001
- As these boats aged and bedding compounds deteriorated, the water torture began, which led to rot, corrosion, and other insidious problems. —Ralph Naranjo, Cruising World, April 1999
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Origin of INSIDIOUS
Latin insidiosus, from insidiae ambush, from insidēre to sit in, sit on, from in- + sedēre to sit — more at sit
Rhymes with INSIDIOUS
Medical Dictionary
insidious
adjective in·sid·i·ous \in-ˈsid-ē-əs\
Medical Definition of INSIDIOUS
: developing so gradually as to be well established before becoming apparent <an insidious disease>
—in·sid·i·ous·ly adverb
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