mindless
adjective(mind-less)
not mindful or attentive
mindless
adjective(mind-less)
not marked by the use of reason
Examples:
Mindless violence. 
mindless
adjective(mind-less)
devoid of intelligence or thought
mindless
adjective(mind-less)
lacking the thinking capacity characteristic of a conscious being
Examples:
The shrieking of the mindless wind. 
mindless
adjective(mind-less)
requiring little mental effort
Examples:
Mindless tasks.