plenary

In the 14th century, the monk Robert of Brunne described a situation in which all the knights of King Arthur's Round Table were present at court by writing, "When Arthures court was plener, and alle were comen, fer and ner. . . ." For 200 years, "plener" (also spelled "plenar") served English well for both senses that we reserve for "plenary" today. But we'd borrowed "plener" from Anglo-French, and, although the French had relied on Latin plenus ("full") for their word, the revival of interest in the Classics during the English Renaissance led scholars to prefer purer Latin origins. In the 15th century, English speakers turned to Late Latin plenarius and came up with "plenary." ("Plenarius" also comes from "plenus," which is the source of our "plenty" and "replenish" as well.)