Not harmful (6)
I believe the answer is:
benign
'not harmful' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for benign that I've seen before include "Medically curable" , "Kindly or non-malignant" , "Meaning no harm" , "Not progressive or dangerous to health" , "Genial, kindly" .)