Thank you Bob for finding those definitions of insidious!
I think I got it 
What's " beguiling" ?

Definitions of beguile on the Web:
juggle: influence by slyness
capture: attract; cause to be enamored; "She captured all the men's hearts"
wordnetweb.princeton.edu/perl/webwn
Deception, beguilement, deceit, bluff, mystification, and subterfuge are acts to propagate beliefs that are not true, or not the whole truth (as in half-truths or omission). Deception can involve dissimulation, propaganda, sleight of hand. It can employ distraction, camouflage or concealment. ...
en.wikipedia.org/wiki/Beguile
To deceive or delude (using guile); To charm, delight or captivate
en.wiktionary.org/wiki/beguile
If you type "define: (word)" into Google it will find answers for you.