As an adjective impervious
is unaffected or unable to be affected by.
As a noun insouciance is
carelessness, heedlessness, indifference, or casual unconcern.
Unaffected or unable to be affected by.
, title=(The Celebrity
, passage=Although the Celebrity was almost impervious
to sarcasm, he was now beginning to exhibit visible signs of uneasiness, the consciousness dawning upon him that his eccentricity was not receiving the ovation it merited.}}
Preventive of any penetration; impenetrable, impermeable, particularly of water.
Immune to damage or effect.
carelessness, heedlessness, indifference, or casual unconcern
* See also