'bugaboo' originates from English, possibly from the Middle English word 'bugge', where 'bugge' meant 'goblin', combined with the exclamation 'boo' or influenced by the word 'bugbear'.

'bugaboo' appeared in early 18th-century English as a dialectal term meaning a bogey or object of terror (similar to 'bugbear') and has been used metaphorically since then to mean a persistent source of fear or annoyance.

Initially it referred to an imaginary frightening creature or bogey ('an object used to frighten'), but over time it evolved into a figurative sense meaning 'a recurring source of worry, annoyance, or obsessive concern.'