Crossword Genius

Unchanging surface with cross removed (7)

Ross

I believe the answer is:

eternal

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'unchanging' is the definition.
(thesaurus)

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(Other definitions for eternal that I've seen before include "Ceaseless" , "One being forever" , "Imperishable" , "with lasting benefit" , "Perpetual" .)

I've seen this clue in The Times.
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