wallflower (n.)youdaoicibaDictYouDict[wallflower 词源字典]
1570s, type of flowering plant cultivated in gardens, native to southern Europe, where it grows on old walls and in rocky places, from wall (n.) + flower (n.). Colloquial sense of "woman who sits by the wall at parties, often for want of a partner" is first recorded 1820.[wallflower etymology, wallflower origin, 英语词源]