The most common and most likely answer to this crossword clue is the 8 letter word SUCCINCT
I've seen this crossword clue in The Daily Telegraph
S
U
C
C
I
N
C
T
More clues leading to the result SUCCINCT
Buddy explains!

The straight part
We know that "brief" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case brief = succinct.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 SUCCINCT mean?
SUCCINCT adjective- Brief and to the point
- Compressed into a tiny area.
- Wrapped by, or as if by a girdle; closely fitting, wound or wrapped or drawn up tightly.