bottomless vs unascertainable

bottomless

adj
  • Difficult to understand; unfathomable. 

  • Extremely deep. 

  • Having no bounds; limitless. 

  • Not wearing clothes below the waist; particularly not wearing clothes that would cover the genitalia. 

  • refillable (usually for iced tea or other such cold beverages) 

  • Having no bottom. 

unascertainable

adj
  • That cannot be ascertained; uncertain, unable to be determined or discovered. 

How often have the words bottomless and unascertainable occurred in a corpus of books? (source: Google Ngram Viewer )