Definition: (adjective) Working or spreading harmfully in a subtle or stealthy manner.
Synonyms: pernicious, subtle.
Usage: He appeared to be recovering, but the insidious disease soon reappeared in his other organs.
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Definition: (adjective) Working or spreading harmfully in a subtle or stealthy manner.
Synonyms: pernicious, subtle.
Usage: He appeared to be recovering, but the insidious disease soon reappeared in his other organs.
Discuss