Definition of ill-behaved:
(adj) :
Indicative of unkind or malevolent intentions; harsh, cruel.
(adj) :
Unpropitious, unkind, faulty, not up to reasonable standard.
(adj) :
Unwell in terms of health or physical condition; sick.
(adj) :
Nauseated; having an urge to vomit.
(adj) :
(slang, chiefly hip-hop) Sublime, with the connotation of being so in a singularly creative way.
(adj) :
(slang) Extremely bad (bad enough to make one ill). Generally used indirectly with to be.