Sentence:  Although the Celebrity was almost impervious to <WSD>sarcasm</WSD>, 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. 
Meaning of the word marked with <WSD> tags:  Use of acerbic language to mock or convey contempt, often using irony and (in speech) often marked by overemphasis and a sneering tone of voice.