be·nign / biˈnīn/ • adj. 1. gentle; kindly: her face was calm and benign. ∎  (of a climate or environment) mild and favorable: ∎  not harmful to the environment: [in comb.] an ozone-benign refrigerant. 2. Med. (of a disease) not harmful in effect: in particular, (of a tumor) not malignant.DERIVATIVES: be·nign·ly adv.

benign XIV. — (O)F, bénigne fem., bénin masc. :- L. benigna, -us, f. roots of bonus good and gignere beget (see KIN). Cf. MALIGN.
So benignant XVIII. benignity XIV. — OF. or L.

benign (bi-nyn) adj.
1. describing a tumour that is not cancerous.

2. describing any disorder or condition that does not produce harmful effects. Compare malignant.