The most common and most likely answer to this crossword clue is the 3 letter word DIS
I've seen this crossword clue in Independent
D
I
S
More clues leading to the result DIS
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 DIS mean?
DIS noun- An insult or put-down; an expression of disrespect.
- To put (someone) down, or show disrespect by the use of insulting language or dismissive behaviour.
- Dissertation.
- An Algerian reedy grass used for cordage.
- Any of a group of minor female deities in Scandinavian folklore.
- This.