Her old freaks, if hinted at, were considered amusing, as one of the irresponsibilities of genius.
Fletcher certainly "loosed the bonds of conduct and left human nature as a mere bundle of irresponsibilities," but not Beaumont.
1640s, "not legally answerable for conduct or actions," from assimilated form of in- (1) "not, opposite of" + responsible. Meaning "not acting with a sense of responsibility" is from 1680s. Related: Irresponsibly.