Smooth down, also up (5)

I believe the answer is:

level

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'smooth down' is the definition.
(thesaurus)

I don't understand the remainder of the clue.

(Other definitions for level that I've seen before include "Neither winning, nor losing" , "Tier; calm and steady" , "Flat and smooth" , "Regular" , "Equal; flat" .)

I've seen this clue in the Evening Standard.

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