The phrase "una tarea de Sísifo" comes from the story of Sisyphus, a character from Greek mythology. In the story, Sisyphus was punished by the gods and condemned to roll a large boulder up a steep hill, only to have it roll back down every time he neared the top. This task was never-ending and futile, symbolizing a cycle of effort and frustration without any meaningful progress.
Therefore, the meaning of the phrase "una tarea de Sísifo" is:
2. una acción Interminable y sin sentido
It refers to a task or action that is endless, repetitive, and ultimately pointless, reflecting the idea of putting in continuous effort without achieving any significant results.