Crossword Genius

Make the speech that’s longest and greatest (9)

Ross

I believe the answer is:

uttermost

I'm a little stuck... Click here to teach me more about this clue!

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

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for uttermost that I've seen before include "at the furthest limit" , "Chief" , "The furthest point or degree" , "Extreme" , "best" .)

I've seen this clue in The Sunday Times.
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.