Insidious (adverb insidiously)

developing in a very gradual, in a stealthy manner, with the intend of causing damage.

Prostate Cancer is an insidious disease.
by piece September 10, 2006
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The Devil's coochie/vagina. Can also be used as an adjective to describe the temperature of the surrounding climate.
It is insidious in my room.
by SexyTexasPete August 29, 2011
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When you touch a chicks rack while their not wearing a shirt... or under a shirt... whatever you want... as long as it's bare-boob touching
I like upstairs insidies because i can touch my girlfriends boobs when her shirts not on.
by Thrashed16 November 25, 2009
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fingering a girls vagina (downstairs) inside her pants (insidies)
Boy: How about some downstairs insidies?

Girl: I'd love to.

*Girl unzips pants*
by dailydoseofwords August 05, 2010
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1. A seemingly impossible to solve problem that no one seems to know the answer to

Bob: Man, this test is hard.

Dan: Yeah, I know. It's insidious puzzlement.

2. A level or puzzle in a videogame that is extremely frustrating.

Josh: I can't figure out how to escape this room! This level is insidous puzzlement!
Definition 1.
Bob: Man, this test is hard.

Dan: Yeah, I know. It's insidious puzzlement.

Definition 2.
Josh: I can't figure out how to escape this room! This level is insidous puzzlement!
by The Anonymous Corporation April 21, 2010
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This person may be confused in life. After watching some cartoons, they may give themself a nickname such as crog the insidious which they think is wicked cool! When needing an attention and or self confidence boost they may shit on the floor or “get schwifty” To Appeal to the small amount of friends he has. If you know a crog the insidious, they probably smell like donkey shit
Omg It was so embarrassing when they called me a crog the insidious

Ew you smell like crog the insidious

I’m not gonna make it to the bathroom, I’m gonna pull a Croft’s the insidious
by Damgiarc May 19, 2019
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