Origin: Latin suffix -ible
Irresponsible has 3 different meanings across 1 category:
Someone who is not responsible.
"The boss fired him for being irresponsible after he left the front door unlocked while everyone was away at work."
showing lack of care for consequences
"behaved like an irresponsible idiot"
"hasty and irresponsible action"
Not responsible; exempt from legal responsibility, not to be held accountable.
"The judge ruled that the corporation was irresponsible for the environmental damage and would not be held liable for any fines."