One is the type of person that cannot keep anything secret.
Another is the sort that always shoots off their mouth to everyone for any reason. Such people tend to get themselves into trouble because they're always pissing people off. The type of person that in an argument will keep arguing and arguing far beyond the point where they've made their point and should stop.
B) This guy I know is always getting into fights because of his big mouth. He'll lip off to anyone for any reason and tends to take arguments a lot farther then any normal person would take them.