run·a·way 
(rŭnə-wā′)
(rŭnə-wā′)n.
1. A person or animal that has run away.
2. Something that has escaped control or proper confinement.
3. Informal An easy victory.
adj.
1. Escaping or having escaped restraint, captivity, or control: runaway horses; runaway children.
2. Out of control: a runaway car; runaway inflation.
3. Easily won: a runaway victory.