Headless; lacking a head or chief. In biology, said of organisms without a distinct "head" region. In politics, of groups and movements without centralized leadership. Acephalous goes beyond simply leaderless: it suggests a structure built to proceed without a single governing crown.

From Greek akephalos “headless,” from a- “without” + kephalē “head,” transmitted through learned Latin and scientific English. The word’s literal anatomy became, readily and often, a political metaphor.