be·nign
 /bıˈnaın/  adj  
  1 medical
  1 a : not causing death or serious injury
   a benign infection/disease
  1 b : without cancer : not cancerous
   benign brain tumors
   We were happy to hear that the tumor was benign.
  — opposite malignant
  2 : not causing harm or damage
   This chemical is environmentally benign. [=it does not hurt the environment]
   He has a benign [=harmless] habit of biting his fingernails.
  3 [more ~; most ~] : mild and pleasant
   benign [=favorable] weather conditions
   a benign climate
  4 [more ~; most ~] : gentle and kind
   a friendly, benign teacher
  5 [more ~; most ~] : having or showing a belief that nothing bad will happen
   She takes a benign view of her husband's spending habits. [=she does not worry about her husband's spending habits]
  be·nign·ly  adv  
   He smiled benignly at his students.