- intended to entrap or beguile: an insidious plan.
- stealthily treacherous or deceitful: an insidious enemy.
- operating or proceeding in an inconspicuous or seemingly harmless way but actually with grave effect: an insidious disease.
Origin of insidious
Synonyms for insidiousSee more synonyms for on Thesaurus.com
Related Words for insidiouslyquietly, clandestinely, surreptitiously, covertly, privately, personally, furtively, stealthily, shrewdly, cunningly, craftily, confidentially, hush-hush, intimately, obscurely, slyly, insidiously, privily, unobserved
Examples from the Web for insidiously
Contemporary Examples of insidiously
Others, more quietly but just as insidiously, operate from the Muslim religious right.Arab Americans Need Political Normalization
November 12, 2012
Historical Examples of insidiously
Are you insidiously advised or tempted to contract it, by any one?Life And Adventures Of Martin Chuzzlewit
And thus a dead point in the revolution of my affairs was insidiously got over.An Outcast of the Islands
Slowly and insidiously it had come to dominate every other problem.
"Better in health, because better in spirits," said the housekeeper, insidiously.Jack Harkaway's Boy Tinker Among The Turks
"There," said Miss Baker, insidiously giving the man two and threepence.The Bertrams
- stealthy, subtle, cunning, or treacherous
- working in a subtle or apparently innocuous way, but nevertheless deadlyan insidious illness
Word Origin for insidious
- Being a disease that progresses with few or no symptoms to indicate its gravity.