insidiousness

insidious | American Dictionary

insidious
adjective
us/ɪnˈsɪd·i·əs/
(of something unpleasant or dangerous) gradually and secretly causing harm:
Cancer is an insidious disease.

insidiously

adverbus/ɪnˈsɪd·i·əs·li/
His negative attitude slowly and insidiously spoiled the atmosphere around the office.

Examples of insidious

insidious
There was too much competition and too few customers, with an insidious effect on prices, wages and working conditions.
We can conclude that the insidious and purposeful attacks were prompted by what psychologists call pre-emptive contempt.
Realized: - that getting tired (a small word to describe such an insidious feeling) takes longer to recover from and takes from many areas.
A more insidious challenge is when the authentic multimer does not exist in the crystal at all.
In this way, the past finds itself trapped within an insidious cultural exchange and sacrificing what integrity it ever had.
Designing special educational strategies requires sensitivity not only to the most sophisticated teaching techniques but also to the insidious effect of attitudes on children's performance.
It is an insidious system of taxation, which discriminates in favour of the rich.
Following publication of the report, the term 'group think' emerged to suggest that a more insidious aspect of the phenomenology of knowledge had been glimpsed.
Once consciousness was sufficiently raised, householders began to take action, to defend their homes against an insidious and dangerous enemy.
Lastly, there is an insidious problem common to all local surveys.
If not addressed effectively, mental health management can thus be a source of insidious insecurity and permanent frustration, affecting both doctor and patient.
Less conspicious but even more insidious are alterations to punctuation and sentence structure that can remove intended meanings or introduce unintended ones.
The range of such thinking, however, is much more insidious.
But again, feminists may respond that ethnocentrism can be the more insidious for being built into politically unreconstructed intellectual agendas.
While habitat preservation must remain the top priority, biologists and conservationists should not neglect to consider the insidious threat of exotic species.
These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors.