Crossword Genius

A bottom one couldn't possibly get beneath? (5)

Ross

I believe the answer is:

nadir

'a bottom' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for nadir that I've seen before include "worst-case scenario?", "deep despair", "Point of greatest despair", "Low spot", "Low point".)

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.