悪性

• Reading: あくせい
• Romaji: akusei
• Kanji breakdown: 悪 (aku/waru) — bad, evil, malicious; 性 (sei) — nature, character, sex
• Pronunciation: /a.kɯ.seː/

Meaning

Malignant; virulent; pernicious. Used in medical contexts to describe dangerous growths or conditions, and figuratively to describe deeply harmful influences.

Most commonly encountered in 悪性腫瘍 (malignant tumour) and 悪性新生物 (malignant neoplasm). Also used outside medicine to describe deeply harmful trends or behaviours. Functions as a noun and na-adjective (悪性の). The opposite is 良性 (benign).

Examples

1. 検査の結果、腫瘍は悪性と診断された。 The test results showed that the tumor was diagnosed as malignant.
2. その組織の悪性の文化が、若手社員を次々と追い込んだ。 The organization's toxic culture drove young employees to the breaking point one after another.
3. 悪性の細菌が抗生物質に耐性を持つようになっている。 Malignant bacteria have been developing resistance to antibiotics.

Usage Guide

Context: medicine, oncology, pathology, social commentary

Tone: clinical

Origin & History

Compound of 悪 (aku, bad/evil) and 性 (sei, nature/character). Together they convey the sense of something having an inherently harmful or dangerous nature.

Cultural Context

Era: Modern

Generation: Adults

Social background: General