The most common and most likely answer to this crossword clue is the 6 letter word MASSES
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More clues leading to the result MASSES
Buddy explains!

The straight part
We know that "Gathers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gathers = masses.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 MASSES mean?
MASSES noun- (physical) Matter, material.
- A large quantity; a sum.
- To form or collect into a mass; to form into a collective body; to bring together into masses; to assemble.
- To have a certain mass.
- The Eucharist, now especially in Roman Catholicism.
- Celebration of the Eucharist.
- (usually as the Mass) The sacrament of the Eucharist.
- A musical setting of parts of the mass.
- To celebrate mass.
- (generically) People, especially a large number of people
- The total population.
- The lower classes or all but the elite.