The most common and most likely answer to this crossword clue is the 10 letter word UNDERSTOOD
I've seen this crossword clue in The Daily Telegraph
U
N
D
E
R
S
T
O
O
D
Buddy explains!

The straight part
We know that "Concluded" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case concluded = understood.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 UNDERSTOOD mean?
UNDERSTOOD verb- To grasp a concept fully and thoroughly, especially (of words, statements, art, etc.) to be aware of the meaning of and (of people) to be aware of the intent of.
- To believe, to think one grasps sufficiently despite potentially incomplete knowledge.
- (obsolete outside circus, acrobatics) To stand underneath, to support.
- Having been comprehended.
- Indicates comprehension on the part of the speaker.