insidiousness insidiously • insight · · · Info · Definitions · Characters · · insidiousness · · Text Latin · · Script 13 · · Length Definitions · · · (noun) subtle and cumulative harmfulness (especially of a disease). · · Noun Definition 1 (noun) the quality of being designed to entrap. · · Noun Definition 2 Characters · · d latin small letter d U+0064 e latin small letter e U+0065 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F s latin small letter s U+0073 u latin small letter u U+0075