The most common and most likely answer to this crossword clue is the 2 letter word US
I've seen this crossword clue in Independent
U
S
More clues leading to the result US
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 US mean?
US pronoun- (personal) Me and at least one other person; the objective case of we.
- (chiefly with give) Me.
- Our.
- Me (in all contexts).