irresponsible

/ˌɪrɪˈspɑnsəbəl/
adjective
  1. Not showing a proper sense of responsibility; not reliable or accountable.
    • It was irresponsible of him to leave the children alone in the house.
    • The driver's irresponsible behavior caused a serious accident.
    • Spending all your savings on a lottery ticket is financially irresponsible.
Antonyms