How to say "benign" in Japanese

• 良性りょうせいCommon
  no-adjectiveCovers the medical sense of 'benign': describing a tumour or growth that is not malignant. This is the common word of the three and the one you want in medical contexts.
• 恵み深いめぐみふかい
  i-adjectiveCovers 'benign' meaning kindly or benevolent, describing a person or manner that is warm and generous. It is less common, and its core sense is really 'gracious', so it fits that flavour of 'benign'.
• 害のないがいのない
  expression, i-adjectiveCovers 'benign' as harmless or innocuous: something that poses no danger or causes no harm. It is less common and literally means 'without harm'; for a tumour, 良性 is the word.

Use 良性 for the medical sense of benign (a growth that is not malignant), 「恵み深い」 for a kindly, gracious person or manner, and 「害のない」 when benign simply means harmless or innocuous.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 良性りょうせいbenign
• 恵み深いめぐみふかいgracious
• 害のないがいのないharmless