• (n.) Increase of irritation or violence, particularly the increase of a fever or disease.
Ex·ac`er·bes'cence noun [ Latin exacerbescens , -entis , present participle of exacerbescere , incho. of exacerbare .] Increase of irritation or violence, particularly the increase of a fever or disease. 
exacerbescence, exacerbescent Showing violence or bitterness; an irritation.