Take no notice (6)
I believe the answer is:
ignore
'take no notice' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ignore that I've seen before include "Deliberately disregard" , "Turn a blind eye to" , "Pay no heed to" , "Disregard - cut" , "'Disregard, overlook (6)'" .)