What is a fiddler?

A Fiddle, as an instrument, is the same as violin. It is called fiddle when associated with certain genres of Folk Music, such as Irish fiddling, Old Time, Bluegrass, Klezmer, Gypsie etc.

A Fiddler is someone who plays fiddle.

In certain slang, also, Fiddling is procrastinating, or getting distracted.

Therefore, sometimes, a fiddler can be someone who does this.