A lot vs. Alot: 9 Grammatical Pitfalls
c.1600, from French explicite, from Latin explicitus "unobstructed," variant past participle of explicare "unfold, unravel, explain," from ex- "out" (see ex-) + plicare "to fold" (see ply (v.1)).
"Explicitus" was written at the end of medieval books, originally short for explicitus est liber "the book is unrolled." As a euphemism for "pornographic" it dates from 1971.
in bookmaking, a device added to the end of some manuscripts and incunabula by the author or scribe and providing such information as the title of the work and the name or initials of its author or scribe. Explicits were soon incorporated into or completely replaced by the colophon, which included information about the printer, printing materials, and typeface, and, often, the printer's emblem