1580s, "one who brings forth a proposition or argument," from Latin proponentem (nominative proponens), present participle of proponere "put forward" (see propound). In part also a native formation from propone. As an adjective, "making proposals," from 1680s.

"proponent or advocate of pacifism," 1903, from French pacifiste (see pacifism). Related: Pacifistic (1902).

1847, "proponent of medieval styles, one who sympathizes with the spirit and principles of the Middle Ages," from medieval + -ist. From 1882 as "one versed in the history of the Middle Ages."