The most common and most likely answer to this crossword clue is the 3 letter word CON
I've seen this crossword clue in The Daily Telegraph
C
O
N
Buddy explains!
The straight part
We know that "fiddle" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fiddle = con.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 CON mean?
CON verb- To study or examine carefully, especially in order to gain knowledge of; to learn, or learn by heart.
- To know, understand, acknowledge.
- A disadvantage of something, especially when contrasted with its advantages (pros).
- (abbreviation) conservative
- A convicted criminal, a convict.
- A fraud; something carried out with the intention of deceiving, usually for personal, often illegal, gain.
- To trick or defraud, usually for personal gain.
- The duty of directing a ship, usually used with the verb to have or to take and accompanied by the article "the."
- To direct a ship; to superintend the steering of (a vessel); to watch the course of (a vessel) and direct the helmsman how to steer (especially through a channel, etc, rather than steer a compass direction).
- An organized gathering such as a convention, conference or congress.
- The conversion of part of a building.
- Consumption; pulmonary tuberculosis.