【敬】對中、老年男性的稱呼（一般是對不相識者）。唔該叔記，南華新街點行啊？（請問大叔，南華新街怎麼走？）

an appellation used to address a middle age or elderly man whose one doesn't know the name of, used in situation such as when talking to a random middle age / elderly man on the street