IRRESPONSIBLE
irresponsible
(adjective) showing lack of care for consequences; “behaved like an irresponsible idiot”; “hasty and irresponsible action”
Source: WordNet® 3.1
Etymology
Adjective
irresponsible (comparative more irresponsible, superlative most irresponsible)
(now, rare) Not responsible; exempt from legal responsibility, not to be held accountable.
Lacking a sense of responsibility; performed or acting as though without responsibility; negligent.
Noun
irresponsible (plural irresponsibles)
Someone who is not responsible.
Source: Wiktionary
Ir`re*spon"si*ble, a. Etym: [Pref. ir- not + responsible: cf. F.
irresponsable.]
1. Nor responsible; not liable or able to answer fro consequences;
innocent.
2. Not to be trusted; unreliable.
Source: Webster’s Unabridged Dictionary 1913 Edition