insidiousness

== English == === Etymology === From insidious +‎ -ness. === Noun === insidiousness (usually uncountable, plural insidiousnesses) A surreptitious harmfulness, quality of entrapment, or treacherousness; the characteristic of being insidious. ==== Translations ==== === References === Noah Webster (1828), “insidiousness”, in An American Dictionary of the English Language: […], volume I (A–I), New York, N.Y.: […] S. Converse; printed by Hezekiah Howe […], →OCLC. “insidiousness”, in Dictionary.com Unabridged, Dictionary.com, LLC, 1995–present.