The most common and most likely answer to this crossword clue is the 3 letter word MOI
I've seen this crossword clue in The Daily Telegraph
M
O
I
More clues leading to the result MOI
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 MOI mean?
MOI pronoun- (often used questioningly to express mock surprise) Me.