ex·ac·er·bate 
(ĭg-zăsər-bāt′)
(ĭg-zăsər-bāt′)tr.v. ex·ac·er·bat·ed, ex·ac·er·bat·ing, ex·ac·er·bates
To increase the severity, violence, or bitterness of; aggravate: a speech that exacerbated racial tensions; a heavy rainfall that exacerbated the flood problems.
[Latin exacerbāre, exacerbāt- : ex-, intensive pref.; see EX- + acerbāre, to make harsh (from acerbus, harsh; see ak- in the Appendix of Indo-European roots).]
ex·ac′er·bation n.