The most common and most likely answer to this crossword clue is the 4 letter word BRER
I've seen this crossword clue in The Guardian
B
R
E
R
More clues leading to the result BRER
Buddy explains!

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 BRER mean?
BRER noun- Son of the same parents as another person.
- A male having at least one parent in common with another (see half-brother, stepbrother).
- A male fellow member of a religious community, church, trades union etc.
- A form of address to a man.
- A black male.
- Somebody, usually male, connected by a common cause or situation.
- Someone who is a peer, whether male or female.