The most common and most likely answer to this crossword clue is the 6 letter word WELDED
I've seen this crossword clue in Independent
W
E
L
D
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More clues leading to the result WELDED
Buddy explains!

The straight part
We know that "stuck together" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case stuck together = welded.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 WELDED mean?
WELDED verb- To join two materials (especially two metals) together by applying heat, pressure and filler, either separately or in any combination.
- To bind together inseparably; to unite closely or intimately.
- To wield.