What is what does it mean to pound sand?

The expression "pound sand" is a dismissive and rude idiom that essentially means "go away and do something pointless and annoying." It is used to tell someone that their opinion is worthless, their actions are inconsequential, or that you simply don't care about what they are saying or doing.

Here's a breakdown:

Meaning: It is a harsh way of telling someone to bother someone else or to engage in a futile activity. The image of pounding sand evokes a sense of useless labor and frustration.
Usage: It's often used when someone is being bothersome, offering unwanted advice, or generally being a nuisance. The speaker is expressing their exasperation and desire for the person to leave them alone. It can also be used as a retort when someone is being arrogant or acting superior.
Connotation: This is a very impolite and confrontational expression. It is best avoided in professional or formal settings. Using the phrase shows a lack of respect.

In essence, "pound sand" is a forceful way to say "get lost" or "I don't care". Think of it as a more colorful and offensive version of "go fly a kite" or "take a hike." Its vulgarity is more explicit than either of these phrases, which makes it a phrase to use with caution.