語源は liberal、free、-ty、名詞接尾辞と同じ。liberalの過剰、不摂生、横柄に由来する。
The spirit of liberty is the spirit which is not too sure it is right. [Learned Hand, 1944]Nautical sense of "leave of absence" is from 1758. To take liberties "go beyond the bounds of propriety" is from 1620s. Sense of "privileges by grant" (14c.) led to sense of "a person's private land" (mid-15c.), which yielded sense in 18c. in both England and America of "a district within a county but having its own justice of the peace," and also "a district adjacent to a city and in some degree under its municipal jurisdiction" (as in Northern Liberties of Philadelphia). Also compare Old French libertés "local rights, laws, taxes."