祝贺 is a verb meaning 'to congratulate'—used when expressing warm wishes to someone who has achieved something positive, such as passing an exam, getting married, or receiving an award. The two characters are near-synonyms: 祝 emphasizes wishing well or blessing (often with ritual or formal overtones), while 贺 conveys celebration and joy in response to good news. Together, they form a standard, polite, and slightly formal compound used widely in spoken and written Chinese.

This word is commonly used in greetings, cards, speeches, and social media posts. It often appears in set phrases like '祝贺你！' (Congratulations to you!) or '向您表示热烈祝贺' (We extend our warmest congratulations to you). Unlike casual expressions like '恭喜', 祝贺 tends to be more measured and appropriate in professional, academic, or ceremonial contexts—but it’s not stiff or archaic, making it versatile for everyday respectful communication.