Sentence:  The humor of my proposition appealed more strongly to Miss Trevor than I had looked for, and from that time forward she became her old self again;.... Our table in the dining-room became again the abode of scintillating wit and <WSD>caustic</WSD> repartee, Farrar bracing up to his old standard, and the demand for seats in the vicinity rose to an animated competition. 
Meaning of the word marked with <WSD> tags:  Sharp, bitter, cutting, biting, and sarcastic in a scathing way.