'bogey' originates from English (influenced by Scots), ultimately related to Middle English 'bugge' and Scots 'bogle' or 'bogley', where those words meant 'goblin' or 'spectre'.

'bugge' (Middle English) developed into Scots 'bogle'/'bogley' and English 'bogey'; in the late 19th century 'bogey' was applied metaphorically in British golf as 'the bogey' (a standard to be beaten) and later became the modern golf term for one over par. The military/aviation use ('unidentified aircraft') developed later by metaphorical extension.

Initially it meant 'goblin' or 'spectre', but over time it came to mean both a general object of fear and specific senses such as the golf score and an unidentified aircraft; the core idea shifted from a frightening creature to an imagined threat or a benchmark/target.