Acerbic and acerb ultimately come from the Latin adjective acerbus, which can mean "harsh" or "unpleasant."  It was formed by adding the suffix "-ic" to the earlier adjective "acerb" (meaning sour) and "acerb" ultimately came from the Latin word "acerbus" meaning harsh or bitter.  Another English word that comes from acerbus is exacerbate, which means "to make more violent or severe. 

The earliest documented use of the word "acerbic" in English dates back to the 1850s.  OED's earliest evidence for acerbic is from 1853, in the writing of G. W. M. Reynolds. acerbic is a borrowing from Latin, combined with an English element.

Examples of Acerbic in a sentence:  
"He instantly wished he could take back the acerbic comment." 
"His question wasn't acerbic, but quite inquisitive." 
"The professor could also be acerbic when challenged."
"Why the need for such acerbic comments?"
"He can be an acerbic critic."
"I love his acerbic humor and his cynicism." 
"As a sufferer of chronic pain, she is acerbic, bitter and savagely funny." 

Just the facts:

ACERBIC Definition & Meaning - Merriam-Webster

They said the head chef was acerbic. I think he's just salty.