Regardless of means without being affected or influenced by something. When you do something regardless of the weather, you're doing it whether it's sunny, rainy, or snowing. The weather doesn't change your plans.

The phrase shows that one thing doesn't depend on another. A teacher might say, “Everyone must follow the classroom rules, regardless of who their friends are.” That means the rules apply equally to everyone: friendships don't matter when it comes to following the rules. A coach might practice with the team regardless of the score from their last game, meaning they'll work just as hard whether they won or lost.

You'll often see this phrase when someone wants to emphasize fairness or determination. “The library is open to all students, regardless of their grades” means every student can use the library, whether they're struggling or excelling. “She kept working on her science project, regardless of the difficulties” shows she didn't let problems stop her.

The phrase is sometimes confused with irregardless, which many people consider incorrect or nonstandard, even though some dictionaries list it. In school and formal writing, it's better to use regardless of.