GNU Collaborative International Dictionary of English

Found one definition

1.       
   Irresponsibility (?), n. [Cf. F. irresponsabilité.]
   1. Lack of, or freedom from, responsibility or accountability.
   
   [1913 Webster]
   
   
   2. A trait causing one to act without a proper sense of responsibility; acting without giving proper weight to one's responsibilities.
   
   [PJC]