1.Definition: easy in mind; not worried
"The prisoner seems entirely unconcerned as to the outcome of the examination"
2.Definition: lacking in interest or care or feeling
"The average American...is unconcerned that his or her plight is the result of a complex of personal and economic and governmental actions...beyond the normal citizen's comprehension and control", "Blithely unconcerned about his friend's plight"
3.Definition: not occupied or engaged with
"Readers unconcerned with style"