n.
 a full, deep, prolonged sound as made by a lion, natural force, or engine. 
▸a loud, deep sound uttered by a person, especially as an expression of pain, anger, or great amusement.
v.
  - make or utter a roar. ▸express in a roar. ▸laugh loudly. ▸(of a horse) make a loud noise in breathing as a symptom of disease of the larynx. 
- (of a vehicle) move with a roar at high speed. ▸act or happen fast and decisively. 
Derivative
  
  Etymology
  OE rārian (v.), imitative of a deep prolonged cry, of W. Gmc origin.