The most common and most likely answer to this crossword clue is the 10 letter word RE-EXAMINE
I've seen this crossword clue in The Guardian
R
E
-
E
X
A
M
I
N
E
More clues leading to the result RE-EXAMINE
Buddy explains!

The straight part
We know that "Double-check" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case double-check = re-examine.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 RE-EXAMINE mean?
RE-EXAMINE verb- To examine again.