Simply from the English word
liberty, derived from Latin
libertas, a derivative of
liber "free". Interestingly, since 1880 this name has charted on the American popularity lists in three different periods: in 1918 (at the end of World War I), in 1976 (the American bicentennial), and after 2001 (during the War on Terrorism).
There were no related names found for Liberty.