knocker
/ˈnɒkə(r)/noun
1
- a metal or wooden instrument hinged to a door and rapped by visitors to attract attention and gain entry门环。
1.1
- informal a person who buys or sells from door to door, especially with intent to deceive〈非正式〉（尤指有意欺诈的）挨门收购（或卖货）的商人。
2
- informal a person who continually finds fault〈非正式〉吹毛求疵的人, 一味找碴儿的人。
3
- ( knockers) informal a woman's breasts〈非正式〉（女人的）一对乳房。
短语
on the knocker
informal <非正式>
1
- Brit. going from door to door canvassing, buying, or selling〈英〉挨家挨户地游说（收购, 卖货）。
2
- Austral./NZ (of payment) immediately; on demand〈澳/新西兰〉（支付）立即; 在要求时：
he has to pay cash on the knocker.
他必须立即支付现金。