1. [late 18C–1900s] a professional perjurer.
2. [1900s–60s] (US) a plaintiff, a prosecutor.
3. [1920s–30s] (US Und.) an informer.
4. [1920s–40s] (US Und.) a judge.
5. [1940s] (US) one who takes or is given the blame for a crime, even if they are not actually guilty.
6. [1960s+] (US) a chatterer, a talker.
7. [1960s+] (US) the voice.
8. [1970s+] (US black) one who talks articulately and persuasively.