responsible is used to refer to individuals or parties who have been entrusted with certain obligations which they must fulfill or answer for. It implies that the desired duties have been assigned or represented by the individual or group, and they must take up the responsibility and execute the desired task.
The responsible headmaster made sure that the school was ready for the parents' meeting.
His responsible behavior earned him the respect of his colleagues.
The responsible parties had to ensure that the project was completed on time.
common mistakes that can be made when using responsible in this capacity include using it with the wrong word order (e.g. 'headmaster responsible' instead of 'responsible headmaster') or overusing it to the point that it becomes meaningless. Remember that responsible should only be used when referring to someone or something that is held accountable for certain duties and obligations.