insidiousness
in·si·dious·ness
noun
1.
subtle and cumulative harmfulness (especially of a disease)
Origin
From insidious + -ness.
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.