"powerful person," 1670s, from Great Mogul (1580s), the common designation among Europeans for the Mongol emperor of India after the conquest of 1520s, from Persian and Arabic mughal, mughul, alteration of Mongol (q.v.), the Asiatic people. As a name for the best quality of playing cards, by 1742, so called for the design on the back.
A Motion was made on behalf of the plaintiff for an injunction to restrain the defendant from making use of the Great Mogul as a stamp upon his cards, to the prejudice of the plaintiff, upon a suggestion, that the plaintiff had the sole right to this stamp, having appropriated it to himself, conformable to the charter granted to the card-makers' company by King Charles the First [Blanchard versus Hill, High Court of Chancery, Dec. 18, 1742]
"elevation on a ski slope," 1961, probably [Barnhart] from Scandinavian (compare dialectal Norwegian mugje, fem. muga, "a heap, a mound"), or [OED] from southern German dialect mugel in the same sense.