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

The straight part
We know that "gathering" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gathering = raking.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 RAKING mean?
RAKING verb- To walk; to roam, to wander.
- Of animals (especially sheep): to graze.
- To roam or wander through (somewhere).
- To act upon with a rake, or as if with a rake.
- To move swiftly; to proceed rapidly.
- Of a bird of prey: to fly after a quarry; also, to fly away from the falconer, to go wide of the quarry being pursued.
- To incline (something) from a perpendicular direction.
- Senses relating to watercraft.
- To behave as a rake; to lead a hedonistic and immoral life.
- The act or process of using a rake; the going over a space with a rake.
- A space gone over with a rake; also, the work done, or the quantity of hay, grain, etc., collected, by going once over a space with a rake.
- Swiftly moving.
- Sloping; having a rake or incline.