gigantic (adj.)
1610s, "pertaining to giants," from Latin gigant- stem of gigas "giant" (see giant) + -ic. Replaced earlier gigantine (c. 1600), gigantical (c. 1600), giantlike (1570s). The Latin adjective was giganteus. Of material or immaterial things, actions, etc., "of extraordinary sine or proportions," by 1797.