Paying no attention (8)
I believe the answer is:
heedless
'paying no attention' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for heedless that I've seen before include "Unconcerned" , "Reckless, careless" , "Paying no attention, to advice or danger" , "Incautious" , "Taking no notice" .)