responsible

adj

1. (postpositional)Having the duty of taking care of something; answerable for an act performed or for its consequences; accountable; amenable, especially legally or politically.

   “Parents are responsible for their child's behaviour.”

2. (postpositional)Being a primary cause of a situation or action and thus able to be blamed or credited for it.

   “Who is responsible for this mess?”

   “[…]Karius was a danger to his own team, responsible for Madrid’s two other goals and last seen wandering aimlessly around the pitch – alone, distraught and clearly traumatised – to ask forgiveness, hands clasped, from the thousands of Liverpool supporters.”

3. Answerable to (a superior).
4. Involving important duties; involving a degree of personal accountability on the part of the person concerned.

   “She has a responsible position in the firm.”

5. Having good judgment in decision-making.

   “But was it responsible governance to pass the Longitude Act without other efforts to protect British seamen? Or might it have been subterfuge—a disingenuous attempt to shift attention away from the realities of their life at sea.”

6. Able to be trusted; reliable; trustworthy.

   “He looks like a responsible guy.”

7. Capable of rational conduct and thus morally accountable for one's behavior.

noun

1. (archaic)The individual who bears the responsibility for something.

   “Were this not so, long since would we have traced directly home the responsibility for the war on Freedom in the Philippines. Long since, would we have hanged the responsibles as traitors to our country.”

2. An actor taking on the lesser roles in repertory theatre.

   “[…] first appeared on August Bank Holiday, 1901, at Grand Theatre, Llandudno, playing "responsibles" with Edward Compton; […]”

   “'Well, the Cardinal is the heavy part, isn't it?' 'I know.' 'Then,' said I, 'you'd better go'; and one of the Responsibles took it on, and was perfect on the night.”