[nok-er] 
| 1. | a person or thing that knocks. |
| 2. | a hinged knob, bar, etc., on a door, for use in knocking. |
| 3. | Informal. a persistent and carping critic; faultfinder. |
| 4. | Slang: Vulgar. a female breast. |
| 5. | on the knocker, British Slang. canvassing or selling door-to-door. |
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