Source : Webster's Revised Unabridged Dictionary (1913)

Haranguer \Ha*rang"uer\, n.
   One who harangues, or is fond of haranguing; a declaimer.

         With them join'd all th' harangues of the throng, That
         thought to get preferment by the tongue. --Dryden.

Source : WordNet®

haranguer
     n : a public speaker who delivers a loud or forceful or angry
         speech