'tearaway' definitions:

adjective

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) [syn: hotheaded, impulsive, impetuous, madcap, tearaway(a), brainish]

noun

A reckless and impetuous person