Mountain most steep, though not the first (7)

I believe the answer is:

everest

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'mountain' is the definition.
(Mount Everest)

I cannot understand how the rest of the clue works.

(Other definitions for everest that I've seen before include "Highest Himalayan mountain" , "Himalayan peak" , "Where Hillary was" , "The world's highest mountain" , "One conquered in 1953" .)

I've seen this clue in The Times.

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