1650s, formed in Eng. from obsolete abysm "bottomless gulf, greatest depths" (c.1300), from O.Fr. abisme (Mod.Fr. abîme), from V.L. *abyssimus (source of Sp., Port. abismo), superl. of L. abyssus or on analogy of Gk.-derived words in -ismus; see
abyss. Weakened sense