Source : Webster's Revised Unabridged Dictionary (1913)

Abysmal \A*bys"mal\, a.
   Pertaining to, or resembling, an abyss; bottomless; unending;
   profound.

         Geology gives one the same abysmal extent of time that
         astronomy does of space.                 --Carlyle.

Source : WordNet®

abysmal
     adj 1: very great; limitless; "abysmal misery"; "abysmal stupidity"
     2: so deep as to be unmeasurable; "the abyssal depths of the
        ocean" [syn: {abyssal}, {unfathomable}]