お疲れ様です (Otsukaresama desu) means "Thank you for your hard work" or "Good work." It's a very common greeting in workplaces, used to acknowledge someone's efforts, whether they are working, finishing work, or just passing by. It shows appreciation for their labor.

仕事や活動を終えた人や、頑張っている人への感謝や労いを表す挨拶です。