devil

The English word devil traces back to Greek diabolos, a noun built from the verb diaballein, "to throw across" and so "to slander" or "to accuse." In Greek texts, diabolos could mean a backbiter, informer, or false accuser. The word named an action before it fixed on a supernatural being. Its earliest life was social and legal, not horned and infernal.

By the 4th century CE, Christian Greek and then Latin writing made Diabolos and diabolus a title for Satan. Jerome's Latin Bible helped spread that form across the western church after about 405 CE. In that setting, the old sense of "slanderer" narrowed into a personal cosmic enemy. The name hardened as theology hardened.

Old English took the word as deofol by around the 9th century, probably through church Latin and early vernacular preaching. Sound changes turned Latin diabolus into a form that fit West Germanic speech. Anglo-Saxon homilies used deofol for the chief evil spirit and for lesser demons as well. The word was already fully naturalized in English before 1000.

Middle English spellings such as devel and devil appear from the 12th and 13th centuries onward. Over time the word widened again, so it could mean Satan, any demon, a wicked person, or a troublesome rascal. That double movement is the whole history in miniature: accusation became a name, and the name became a common noun. The old charge still echoes inside the modern word.