The most common and most likely answer to this crossword clue is the 11 letter word OBSERVATION
I've seen this crossword clue in The Guardian
O
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More clues leading to the result OBSERVATION
Buddy explains!

The straight part
We know that "comment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case comment = observation.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 OBSERVATION mean?
OBSERVATION noun- The act of observing, and the fact of being observed (see observance)
- The act of noting and recording some event; or the record of such noting.
- A remark or comment.
- A judgement based on observing.
- Performance of what is prescribed; adherence in practice; observance.
- A regime under which a subject is routinely observed.
- Philosophically as: the phenomenal presence of human being existence.