If you fiddle with an object, you keep moving it or touching it with your fingers.

If you fiddle with something, you change it in minor ways.

If you fiddle with a machine, you adjust it.

If someone fiddles financial documents, they alter them dishonestly so that they get money for themselves.

A fiddle is a dishonest action or scheme in which someone gets money for themselves.

If something is a fiddle, it is quite difficult to do because it involves small or complicated objects.

Some people call violins fiddles, especially when they are used to play folk music.

Someone who is as fit as a fiddle is very healthy and full of energy.

If someone is on the fiddle, they get money by doing illegal or dishonest things.

If you say that someone is fiddling while Rome burns, you mean that they are not dealing with a difficult or dangerous situation but instead are doing useless things or pretending that nothing is wrong.

If you play second fiddle to someone, your position is less important than theirs in something that you are doing together.

If you fiddle around or fiddle about with a machine, you do things to it to try and make it work.

If someone fiddles around or fiddles about, they waste time doing unimportant things instead of dealing with important problems.

If you say that someone is fiddling around with or fiddling about with something, you mean that they are changing it in a way that you disapprove of.