借題發揮

Simplified: 借题发挥

jiètífāhuī ㄐㄧㄝˋ ㄊㄧˊ ㄈㄚ ㄏㄨㄟ

    • to use the current topic to put over one's own ideas
    • to use sth as a pretext to make a fuss

Character by character

Sources