The most common and most likely answer to this crossword clue is the 10 letter word LOOSE-LEAF
I've seen this crossword clue in The Guardian
L
O
O
S
E
-
L
E
A
F
More clues leading to the result LOOSE-LEAF
- For this type of folder John feels a rebinding is needed
- It may drop at any time, having no binding
- Sort of folder seen in the autumn?
- Easily removable WC with false nuts round tip of base
- Extensively used sort of folder, found abandoned on table extension?
- Some folders are found in tea after teabag malfunction
Buddy explains!

The straight part
We know that "Sort of folder" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sort of folder = loose-leaf.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 LOOSE-LEAF mean?
LOOSE-LEAF adjective- (of a plant or a tea) that has loosely connected or separate leaves
- Consisting of loose leaves (pages), often collected in a binder, rather than being bound like a book or stapled.