Benign means gentle and harmless. A benign smile, a benign climate, a benign tumour.
In medicine it is the crucial word: a benign tumour does not invade or spread, and the whole point of a biopsy is to tell benign from malignant. Outside medicine it means kindly or harmless — benign neglect, a benign influence. Note malign and malignant, which are the opposites in both senses; and that benign comes from the Latin for well-born, which is where its kindliness comes from.
1adjectivebenignGentle and harmless.
“The island has a benign climate, with mild winters and warm, dry summers.”
2adjectivecancerousNot cancerous, of a growth.
“The doctor told her the lump was benign and nothing to worry about.”
benign is a quality of harmlessness.
Latin benignus is bene, well, plus a form of genus, birth — well-born, and so kindly. Malign is its exact opposite, built the same way.
Latin
benignus — kind, good
Old French
benigne
Middle English
benigne
English, today
benign
Built from
From Middle English benigne, benygne, from Old French benigne, from Latin benignus (“kind, good”), from bene (“well”) + genus (“origin, kind”). Compare malign.
Etymology from Wiktionary, CC BY-SA