Gloss · Words · Insidious

insidious

ɪnˈsɪdiəsadjective

What does insidious mean?

Spreading harm slowly and quietly, so you do not notice.

Insidious, six ways

PlainSpreading harm slowly and quietly, so you do not notice.
ADHDQuiet harm. Creeps in. You don’t see it coming.
Gen ZThe kind of bad that creeps in while you think everything is fine.
MetaphorRust under the paint.
FormalProceeding in a gradual, subtle way, but with harmful effects.
Like I’m 5Something bad that sneaks in little by little, so you don’t notice. That’s insidious.

How to pronounce insidious

in-SID-ee-us/ɪnˈsɪdiəs/

Insidious in a sentence

The disease is insidious in its early stages.
Doubt is insidious: it starts small.
Insidious diseases show few early symptoms.

Synonyms for insidious

stealthyQuiet and unseen, neutral.
perniciousSeriously harmful, not necessarily hidden.
creepingGradual, plainer.

Pernicious vs insidious: Insidious is about how the harm arrives: slowly, unnoticed. Pernicious is about how bad it is. The difference, in plain English.

Where insidious comes from

Latin. Insidiae, an ambush, from insidere, to sit in wait.

Good to know

Insidious is about how harm arrives: slowly and unnoticed. Pernicious is about how bad it is.

Insidious meaning, on a Gloss card: Spreading harm slowly and quietly, so you do not notice.

Save the card

Insidious on one card: what it means, how to say it, and a sentence. Keep it, or pin it for later.

Download the card Pin it

Coming to the App Store

Gloss explains every word like this, in the style you choose, and brings it back until it stays. A word of the day on your home screen, games that build your vocabulary, no ads. For iPhone, free for three days.

Words like insidious

pernicious · clandestine · surreptitious · juxtaposition · ineffable · somnolent · All 110 words

In: Words for ideas · SAT words