freelance

From free + lance. The word was coined by Walter Scott in his 1819 novel Ivanhoe, describing a medieval mercenary warrior — a "free-lance" — whose weapon was pledged to no lord's service.

It shifted into a figurative noun around the 1860s, and by 1903 it was recognized as a verb. Since then it has spread further into an adjective and an adverb, along with the derived noun freelancer.

The clearest relative is its own offspring, freelancer, formed once the word settled into everyday use.