A capriccio
A capriccio is a tempo marking indicating a free and capricious approach to the tempo of the piece. This marking will usually modify another, such as lento a capriccio, often used in the Hungarian Rhapsodies of Franz Liszt. Perhaps the most famous piece to use the term is Ludwig [van Beethoven]'s ""Rondo alla ingharese quasi un capriccio", Op. 129, better known as "Rage Over a [Lost Penny]".