'Irresponsible' definitions:

Definition of 'irresponsible'

From: WordNet
adjective
Showing lack of care for consequences; "behaved like an irresponsible idiot"; "hasty and irresponsible action" [ant: responsible]

Definition of 'Irresponsible'

From: GCIDE
  • Irresponsible \Ir`re*spon"si*ble\, a. [Pref. ir- not + responsible: cf. F. irresponsable.]
  • 1. Not responsible; not liable or able to answer for consequences; innocent. [1913 Webster]
  • 2. Not to be trusted; unreliable; lacking a proper sense of responsibility. [1913 Webster]