bub
/bʌb/noun
- N. Amer. informal an aggressive or rude way of addressing a boy or man〈北美, 非正式〉老弟; 小家伙（一种具有挑衅性或粗鲁的称呼方式）：
hey, bub, I'm looking for someone.
嗨！老弟, 我正在找人。
词源
mid 19th cent.: from earlier bubby （perhaps a child's form of BROTHER）， or from German Bube 'boy'.