bottomless

Short definition from Wiktionary

Adjective

1. 1
   Having no bottom.
2. 2
   Extremely deep.
3. 3
   Having no bounds; limitless.
4. 4
   Of a meal: accompanied by unlimited drinks.
5. 5
   Difficult to understand; unfathomable.
6. 6
   refillable (usually for iced tea or other such cold beverages)
7. 7
   Not wearing clothes below the waist; particularly not wearing clothes that would cover the genitalia.