Germanic people who lived in Eastern Europe c. 100 A.D. (O.E. Gota, L.L. Goth, Gk. Gothoi), from Goth. gutþiuda "Gothic people," the first element cognate with O.N. gotar "men". "The sense 'men' is usually taken to be the secondary one, but as the etymology of the word is unknown, this is uncertain" [Gordon
]. The unhistorical -th- in Eng. is from L.L. Used in sense of "savage despoiler" (1663) in reference to their sack of Roman
cities, 5c. Gothic was used by scholars to mean "Germanic, Teutonic" (1647), hence its evolution as a term for the art style that emerged in northern Europe in the Middle Ages, and the early 19c. literary style that used medieval settings to suggest horror and mystery. The word was revived 1983 as the name for a style of music and the associated youth culture; abbreviated form goth is attested from 1986. Gothic revival in reference to architecture and decorating first recorded 1869 in writing of C.L. Eastlake.
from etymonline.com :o)