related to or resembling an abyss bottomless unending powerful
- extremely great; endless
- resembling an abyss thorough; so deep concerning be unmeasurable
- regarding, or resembling, an abyss; bottomless; unending; serious.
1650s, formed in English from abysm + -al (1). Weakened sense of "extremely bad" is first taped 1904, possibly from abysmal lack of knowledge (suggestive of its "depth"), a manifestation attested from 1847. Relevant: Abysmally.
(a.) with respect to, or resembling, an abyss; bottomless; unending; powerful.
Thus although the rocks of the southern coast of Java in their general character and succession resemble those of Christmas Island, there lies between them an abysmal trough 18,000 ft.