不可逆

• Reading: ふかぎゃく
• Romaji: fukagyaku
• Kanji breakdown: 不 (fu) — negation prefix; 可 (ka) — possible; 逆 (gyaku/saka) — reverse, contrary
• Pronunciation: /ɸɯ.ka.ɡja.kɯ/

Meaning

Irreversible; non-reversible. Describes a process or change that cannot be undone or returned to its original state.

A na-adjective used primarily in scientific, philosophical, and policy contexts. 不可逆的な変化 (irreversible change) is a standard collocation in environmental science, chemistry, and historical analysis. The word carries a weighty, final quality — once something is 不可逆, there is no going back. Formal and technical in register.

Examples

1. 地球温暖化がある一定の閾値を超えると、不可逆的な変化が起こる可能性がある。 If global warming exceeds a certain threshold, irreversible changes may occur.
2. 神経細胞の損傷は多くの場合、不可逆的であるため早期治療が重要だ。 Damage to nerve cells is often irreversible, making early treatment critical.
3. 歴史的な和解の機会を逃したことは、不可逆的な損失だと専門家は言う。 Experts say that missing the opportunity for a historic reconciliation was an irreversible loss.

Usage Guide

Context: science, environment, medicine, philosophy, history

Tone: neutral

Origin & History

Compound of 不 (fu, not/un-) + 可 (ka, possible/allowed) + 逆 (gyaku, reverse). Literally 'not possible to reverse.' A technical compound coined in modern Japanese to translate concepts from Western science and philosophy.

Cultural Context

Era: Modern

Generation: Adults

Social background: Educated