IPA: /ˈbʌɡbɛə/
KK: /ˈbʌɡˌbɛr/
A source of fear or annoyance, often imagined or exaggerated, that causes worry or distress.
The constant noise from the construction site became a bugbear for the residents.
Bugbear is formed from "bug" (from Middle English *bugge*, meaning a frightening creature or goblin) and "bear" (from Old English *bera*, meaning a large mammal). The term originally referred to a frightening creature, combining the idea of a scary being with the bear, which is often seen as a fearsome animal.
Think of a 'frightening creature' ('bug') combined with a 'large mammal' ('bear') — that's why a bugbear is something that scares you.
No commonly confused words.