Smooth and tough Arctic explorer saving lives, originally (6)

I believe the answer is:

pearly

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'smooth' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I don't see?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for pearly that I've seen before include "to reach such gates, one'll be late" , "decorated with gems" , "Like the gates of heaven?" , "These gates are heavenly" , "Like heaven's gates?" .)

I've seen this clue in The Telegraph.

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