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insidious

Adjective

IPA /ɪnˈsɪdiəs/

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Meaning in plain English

Developing gradually and quietly in a way that is difficult to notice but can cause serious harm.

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Pronunciation

insidious/ɪnˈsɪdiəs/

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Damp develops behind a wall
The damage spreads unnoticed
Serious damage becomes visible

An insidious problem causes harm gradually before people recognise it.

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The insidious spread of damp damaged the wall before we noticed it.
Repeated rumours had an insidious effect on trust within the team.

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The ________ spread of damp damaged the wall before we noticed it.

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insidious — Developing gradually and quietly in a way that is difficult to notice but can cause serious harm.

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Developing gradually and quietly in a way that is difficult to notice but can cause serious harm.

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Word origin

From Latin insidiosus, related to insidiae, meaning an ambush or trick.

Did you know?

Insidious often describes a process, influence or effect whose harm becomes clear only later.

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