叛乱 (pàn luàn) is a formal noun meaning 'rebellion' or 'revolt' — an organized, often armed, uprising against an established government or authority. The first character 叛 (pàn) means 'to betray' or 'to rebel', carrying strong connotations of disloyalty and defiance; the second character 乱 (luàn) means 'chaos', 'disorder', or 'turmoil'. Together, they emphasize both the act of breaking allegiance and the resulting social instability. This term is typically used in historical, political, or journalistic contexts — not for casual disagreements or minor protests.

叛乱 implies serious, large-scale resistance with intent to overthrow or challenge legitimate rule. It appears frequently in textbooks, news reports about civil unrest, and historical accounts of dynastic collapses or colonial resistance. Because of its gravity, it’s rarely used metaphorically and never in lighthearted or personal contexts — saying someone ‘started a rebellion’ over a small issue would sound absurdly exaggerated in Chinese.