Old English hænep "hemp, cannabis sativa," from Proto-Germanic *hanapiz (source also of Old Saxon hanap, Old Norse hampr, Old High German hanaf, German Hanf), probably a very early Germanic borrowing of the same Scythian word that became Greek kannabis (see cannabis). As the name of the fiber made from the plant, by c. 1300. Slang sense of "marijuana" dates from 1940s; scientific applications for the narcotic derived from hemp date to 1870.
suffix added to nouns to produce adjectives meaning "made of, of the nature of" (such as golden, oaken, woolen), corresponding to Latin -anus, -inus, Greek -inos; from Proto-Germanic *-ina- (from PIE *-no-, adjectival suffix).
Common in Old, Middle, and early Modern English: e.g. fyren "on fire; made of fire," rosen "made or consisting of roses," hunden "of dogs, canine," beanen "of beans," baken "baked," breaden "of bread;" Wyclif has reeden made of or consisting of reeds." The few surviving instances are largely discarded in everyday use, and the simple form of the noun doubles as adjective (gold ring, wool sweater). Some are used in special contexts (brazen, wooden).
<a href="https://www.etymonline.com/word/hempen">Etymology of hempen by etymonline</a>
Harper, D. (n.d.). Etymology of hempen. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/hempen