Sharp, biting, or acid in temper, expression or tone.

***My thoughts on this word: Sometimes one comes across a word or phrase that seems to sum up ones self in such a way as to amaze and gratify. When I stumbled upon this word, I was instantly reminded that I am not only sarcastic in my normal speach, but acerbic as well.  Sarcasim and acerbic are closely related. Like second cousins; far enough apart to be wanting, but too close to marry. There are times when I catch myself thinking I have been sacrastic, when in reality, I am in fact, being acerbic.