The most common and most likely answer to this crossword clue is the 3 plus 3 letter word OFF KEY
I've seen this crossword clue in The Daily Telegraph
O
F
F
K
E
Y
More clues leading to the result OFF KEY
Buddy explains!
The straight part
We know that "played badly" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case played badly = off key.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 OFF KEY mean?
OFF KEY adjective- Pitched inaccurately either above or below the correct note
- (by extension) not harmonious, or out of accord