Which term suggests to play with a heavy emphasis?

The term "Pesante" is used in music to indicate a heavy, weighty, or strongly emphasized manner of playing. When a composer uses this term, it instructs the performer to apply a considerable amount of emphasis, making the passage sound more robust and forceful. This can add drama and intensity to the music, which is particularly effective in certain styles or passages.

In contrast, the other terms do not convey the same idea of heavy emphasis. "Pianissimo" refers to a very soft dynamic, suggesting gentleness rather than weight. "Peso," while it might seem related, is not a standard musical term in this context and does not convey the intended meaning. "Con moto" indicates a lively or brisk tempo but does not imply heavy emphasis. Therefore, "Pesante" is the most appropriate choice for conveying the concept of playing with a heavy emphasis.