(of a person, attitude, or action) not showing a proper sense of responsibility.
It's irresponsible to leave small children alone.
Leaving a campfire unattended is irresponsible and poses a significant fire risk.
Irresponsible use of resources can lead to environmental degradation.
An irresponsible driver endangers not only themselves but also others on the road.
Irresponsible financial management can result in long-term consequences.