The most common and most likely answer to this crossword clue is the 10 letter word DISCOVERER
I've seen this crossword clue in The Times
D
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More clues leading to the result DISCOVERER
Buddy explains!

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 DISCOVERER mean?
DISCOVERER noun- One who discovers: a person who has discovered something.