Karloff, BorisKar‧loff, Bor‧is /ˈkɑːlɒf $ ˈkɑːrlɔːf, -ɑːf, ˈbɒrɪs $ ˈbɔː-/(1887–1969) a British actor, who is known for his work in US horror films (=films that are intended to make you feel frightened), and who is especially famous for appearing as the monster in the film Frankenstein (1931)