The most common and most likely answer to this crossword clue is the 10 letter word INSULATING
I've seen this crossword clue in The Guardian
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More clues leading to the result INSULATING
Buddy explains!
The straight part
We know that "protecting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case protecting = insulating.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INSULATING mean?
INSULATING verb- To separate, detach, or isolate.
- To separate a body or material from others, e.g. by non-conductors to prevent the transfer of electricity, heat, etc.
- That insulates.