It is uncertain when the exact first usage of the boogeyman was. Some sources date it as far back as the 16th century, while other sources indicate it was first used as a term for the devil around 1836.
The etymology of the word "boogeyman" is from Middle English. It means frightening spectre. This does lend itself to being a ghost-like creature. However, the boogeyman is rarely given a firm description, as it is most often used as a vague term that takes the shape of whatever a child fears the most. This allows parents to use the boogeyman as a tool to curb misbehavior from their children by using fear as a motivating factor.