bugbear
/ˈbʌgbeə(r)/noun
1- a cause of obsessive fear, irritation, or loathing使人过分害怕（或恼怒、憎恶）的东西。
1.1
- archaic an imaginary being invoked to frighten children, typically a sort of hobgoblin supposed to devour them〈古〉（用以吓唬孩子的）臆造的怪物（尤指一种据说会吞食孩子的妖怪）。
词源
late 16th cent.: probably from obsolete bug 'bogey' (of unknown origin) + BEAR2.