re·spon·si·bil·i·ty 
/rɪˌspɑ:nsəˈbɪləti/ noun
plural re·spon·si·bil·i·ties /rɪˌspɑ:nsəˈbɪləti/ noun 1 [noncount] : the state of being the person who caused something to happen
▪ He accepted full responsibility for the accident. [=he admitted that the accident was his fault] ▪ The boys denied any responsibility for the damage to the fence. ▪ A terrorist group has claimed responsibility for the bombing. 2 a : a duty or task that you are required or expected to do [count] ▪ The janitor has many responsibilities. ▪ Mowing the lawn is your responsibility. ▪ She has to deal with a lot of family and work responsibilities. ▪ It is your responsibility to give the company two weeks notice if you decide to leave. ▪ A teacher's most important responsibility is to help her students. = A teacher's first responsibility is to/toward her students. [noncount] ▪ In her new position, she will have much more responsibility.
b [count] : something that you should do because it is morally right, legally required, etc.
▪ We have a responsibility to protect the environment. ▪ The government's responsibility is to serve the public. 3 [noncount] : the state of having the job or duty of dealing with and taking care of something or someone
▪ The principal has responsibility for 450 students and a staff of 35. 4 [noncount] : the quality of a person who can be trusted to do what is expected, required, etc.
▪ She is completely lacking in responsibility. ▪ The boy developed a sense of responsibility with his first job.
▪ He accepted full responsibility for the accident. [=he admitted that the accident was his fault] ▪ The boys denied any responsibility for the damage to the fence. ▪ A terrorist group has claimed responsibility for the bombing.
b [count] : something that you should do because it is morally right, legally required, etc.
▪ We have a responsibility to protect the environment. ▪ The government's responsibility is to serve the public.
▪ The principal has responsibility for 450 students and a staff of 35.
▪ She is completely lacking in responsibility. ▪ The boy developed a sense of responsibility with his first job.
on your own responsibility
◊To do something on your own responsibility is to do it without being told to and to accept the blame if it has a bad result.
▪ He changed the schedule on his own responsibility.
▪ He changed the schedule on his own responsibility.
