runaway
run‧a‧way1 /ˈrʌnəweɪ/ 
adjective [only before noun]
1. a runaway vehicle or animal is out of control:
a runaway horse
2. happening very easily or quickly, and not able to be controlled:
The film was a runaway success.
runaway inflation
a runaway victory
3. a runaway person has left the place where they are supposed to be ⇨ run away
runaway2 noun [countable]
someone, especially a child, who has left home without telling anyone and does not intend to come back
⇨ run away at run1
| I |
adjective [only before noun]1. a runaway vehicle or animal is out of control:
2. happening very easily or quickly, and not able to be controlled:
3. a runaway person has left the place where they are supposed to be ⇨ run away
| II |
noun [countable]someone, especially a child, who has left home without telling anyone and does not intend to come back
⇨ run away at run1