1375-1425; (v.) late Middle Englishpurporten < Anglo-Frenchpurporter to convey, equivalent to pur-pro-1 + porter to carry (< Latinportāre); (noun) late Middle English < Anglo-French, derivative of the v.
early 15c., from Anglo-French purport (late 13c.), Old French porport "contents, tenor," back-formation from purporter "to contain, convey, carry," from pur- (from Latin pro- "forth;" see pur-) + Old French porter "to carry," from Latin portare "to carry" (see port (n.1)).
early 15c., "indicate, express, set forth," from the noun in English and from Anglo-French purporter (c.1300), from Old French purporter (see purport (n.)). Related: Purported; purporting.