The most common and most likely answer to this crossword clue is the 10 letter word OPEN-ENDED
I've seen this crossword clue in The Times
O
P
E
N
-
E
N
D
E
D
More clues leading to the result OPEN-ENDED
- Old writer finished, with more that might be written
- What finally happened at St Andrews, say, is ill-defined
- Began to admit part in allowing free expressions of opinion
- Golf tournament finished with no obvious result
- Frank finished with no definite conclusion
- Without fixed limits, start over
- Began to check boundary not rigorously fixed
- Start over with no restrictions
- Start to finish, journalist is not restrained by limits
- Changeable writer to stop going through dictionary
Buddy explains!

The straight part
We know that "with more that might be written" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case with more that might be written = open-ended.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 OPEN-ENDED mean?
OPEN-ENDED adjective- Unrestricted by definite limits.
- Adaptable to change.
- Permitting a spontaneous or unstructured response.
- Of a straight draw, made up of four consecutive cards, thus able to be completed by either of two ranks of card.