roar 
(rôr)
(rôr)n.
1. The loud deep cry of a wild animal, especially a lion or other wild cat.
2. A loud, deep, prolonged sound or cry, as of a person in distress or rage.
3. A loud prolonged noise, such as that produced by waves.
4. A loud burst of laughter.
v. roared, roar·ing, roars
v.intr.
1. To produce or utter a roar.
2. To laugh loudly or excitedly.
3. To make or produce a loud noise or din: The engines roared.
4. To move while making a loud noise: The truck roared down the road.
5. To breathe with a rasping sound. Used of a horse.
v.tr.
Phrasal Verb: 1. To utter or express loudly. See Synonyms at yell.
2. To put, bring, or force into a specified state by roaring: The crowd roared itself hoarse.
roar back
To have great success after a period of lackluster performance; make a dramatic recovery: lost the first set but roared back to win the match.
[Middle English roren, to roar, from Old English rārian.]
roarer n.