teflon
1. [ adjective ] not to be trusted
Synonyms: tricky slippery
Examples:

"how extraordinarily slippery a liar the camera is"- James Agee "they called Reagan the teflon president because mud never stuck to him"

Related terms: untrustworthy
2. [ noun ] (trademark) a material used to coat cooking utensils and in industrial applications where sticking is to be avoided
Synonyms: polytetrafluoroethylene
Related terms: plastic trademark