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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; see sed- in Indo-European roots.]

in·sid′i·ous·ly adv.
in·sid′i·ous·ness n.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.insidiousness - subtle and cumulative harmfulness (especially of a disease)
harmfulness, injuriousness - destructiveness that causes harm or injury
2.insidiousness - the quality of being designed to entrap
perfidiousness, perfidy, treachery - betrayal of a trust
References in periodicals archive ?
of the Ateneo de Manila University School of Government - as cited by Inquirer columnist Cielito Habito, highlighted the particular insidiousness of the Philippine experience: 'Cross-country comparisons suggest that the Philippines has been unusually more prone to political dynasties than other countries .
The Milan's court acquittal of Luca Volonte, the former chair of the European People's Party group in PACE, who was accused of corruption ties with Azerbaijan, once again exposed the lies and insidiousness of Armenians and pro-Armenian forces, Azerbaijani MP Elman Nasirov told Trend on Feb.
The insidiousness of cybercrime encompasses the incessant probing for vulnerable data and systems such as the exposure of 123 million households' data and a recently discovered printer spoofing operation.
Truly, the harrowing failure of the Muslim governments/leaderships in the Middle East to rationally respond to the challenges of western engineered imperialism/intervention in the region remains one of the driving causes of Trump's shown insidiousness on Jerusalem.
Of course he's funny, but that doesn't mean this representation is accurate or right or righteous," Kondabolu told the BBC, adding that it demonstrated "the insidiousness of racism .
In this, rather its absence, we find the insidiousness of the world literature anthology.
The insidiousness of relational egalitarianism lies in its approach to distribution.
The paper concludes with some remarks about the social and political insidiousness of cryptonormativity, looking forward to future work.
31) Given Red's own brutal abuse of all his children, his promptness to blame the victim is not surprising, but when both victims of his sexual abuse--Dinah and Sorrel--hold Red's point of view, the insidiousness, isolation, and pervasive effects of incest are glaringly evident.
My counterstories sought to document my perspective of the insidiousness of interest convergence at work within a state's educational system fighting against change and to maintain the status quo.
Charlie Freeman's beautiful prose and surprising characters would distinguish it amongst its peers in any circumstances, but its focus on race renders it crucial, timely reading for all those who question, or who wish to discuss, the persistence of prejudice, or the insidiousness of its movements.
To Berlioz, as to others of his generation, the worrisome notion of "Otherness" that marks much modern discourse on the arts and humanities, and that serves productively to promote awareness of the insidiousness of linking alterity and subservience, was no worry at all.