USA, 1883—exclamation of surprise at seeing something or somebody unexpected—alludes to a hunter who will lament seeing all sorts of game when he goes out into the woods and fields without his gun
1894—(depreciative) someone who has a controlling influence over another—from the name of the hypnotist under whose spell Trilby falls in ‘Trilby’ (1894), by George Du Maurier
21st century: the practice of maintaining a certain distance between oneself and other people in order to prevent infection with a disease—20th century: the practice of maintaining a degree of remoteness or emotional separation from another person or social group