ir·re·spon·si·ble 
(ĭr′ĭ-spŏnsə-bəl)
(ĭr′ĭ-spŏnsə-bəl)adj.
1. Marked by a lack of responsibility: irresponsible accusations.
2. Lacking a sense of responsibility; unreliable or untrustworthy.
3. Not liable to be called to account by a higher authority.
n.
1. One who has no sense of responsibility.
2. One who is unlikely to be called to account by a higher authority.
ir′re·spon′si·bili·ty, ir′re·sponsi·ble·ness n.
ir′re·sponsi·bly adv.