Responsible means being in charge of something and answerable if it goes wrong. Responsible for the accounts, who is responsible for this?, a responsible position.
It splits into three uses that all take different prepositions or none. Responsible for something means in charge of it. Responsible to somebody means answerable to them. And responsible on its own describes a person who can be trusted — a responsible adult, act responsibly. Note that being responsible for a problem means being to blame, while being responsible for a task means being in charge, and only context separates them. The noun is responsibility.
1adjectiveresponsibleIn charge of something and answerable for it.
“She is responsible for the whole department.”
synonyms: in charge of, accountable
2adjectivecauseBeing the cause of something bad.
“Nobody knows who was responsible for the damage.”
3adjectivesensibleSensible and able to be trusted.
“He is old enough to be responsible about it.”
Too few real examples of this word to estimate which sense is commonest.
responsible is a state of being answerable.
Latin respondere meant to answer — the same verb behind respond and response. Somebody responsible is somebody who has to answer for it, and every English sense is still that: it is about who takes the question when it comes.
Latin
responsus
Old French
responsable
Middle French
responsable
English, today
responsible
From Middle French responsable, from Old French responsable, responsible, formed from the root of Latin responsus, from respondeō. The spelling of the English word is taken from the Old French variant responsible. by surface analysis, response + -ible.
Etymology from Wiktionary, CC BY-SA