Definition: A code-mixing term that Hong Kong students like use to refer to highlighting important information with a highlighter pen. (瑩光筆）Usage: E.g. 學生：等我highlight句野先，方便溫書嗰陣時。
老師：考試時記住帶返支highlighter。冇既就要underline架喇。Reference: https://www.weekendhk.com/weekspecial/中英夾雜-港式廣東話-香港人-ctb081-hc-1413297/3/
