If you refer to a young person as a tearaway, you mean that they behave in a wild and uncontrolled way.
例句
He blamed lack of parental control for the young tearaways' behaviour.他認為，那些小流氓行為不端是因為缺少家教。
英英詞典釋義
Noun
1. a reckless and impetuous person
Adjective
1. characterized by undue haste and lack of thought or deliberation;
"a hotheaded decision""liable to such impulsive acts as hugging strangers""an impetuous display of spending and gambling""madcap escapades"; (`brainish' is archaic)