The Collaborative International Dictionary of English v.0.48:

Clysmian \Clys"mi*an\, a. [Gr. ? a place washed by the waves,
   fr. ?. See Clyster.]
   Connected with, or related to, the deluge, or to a cataclysm;
   as, clysmian changes. --Smart.
   [1913 Webster]