What does Boxing Day have to do with boxing?
early 15c., from Anglo-French paisant (mid-14c.), Old French paisent "local inhabitant" (12c., Modern French paysan), earlier paisenc, from pais "country, region" + Frankish suffix -enc "-ing."
Pais is from Late Latin pagensis "(inhabitant) of the district," from Latin pagus "country or rural district" (see pagan). As a style of garment in fashion (e.g. peasant blouse) from 1953.