The most common and most likely answer to this crossword clue is the 10 letter word BUTTRESSES
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More clues leading to the result BUTTRESSES
Buddy explains!

The straight part
We know that "Supports" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case supports = buttresses.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 BUTTRESSES mean?
BUTTRESSES noun- A brick or stone structure built against another structure to support it.
- Anything that serves to support something; a prop.
- A buttress-root.
- A feature jutting prominently out from a mountain or rock; a crag, a bluff.
- Anything that supports or strengthens.
- To support something physically with, or as if with, a prop or buttress.
- (by extension) To support something or someone by supplying evidence; to corroborate or substantiate.