严谨 (yán jǐn) is an adjective meaning 'rigorous' or 'strict (in method)', especially in contexts requiring precision, carefulness, and adherence to standards. The first character 严 means 'strict' or 'severe', while 谨 means 'cautious', 'prudent', or 'scrupulous'. Together, they emphasize a disciplined, thorough, and error-averse approach—not merely strictness for its own sake, but methodical accuracy and intellectual integrity.

This word is commonly used to describe academic research, scientific methodology, medical procedures, legal reasoning, engineering design, or any process where consistency and reliability are essential. It carries a positive, respectful connotation—someone described as 严谨 is admired for their reliability and attention to detail. Unlike casual words like 认真 (serious), 严谨 implies higher stakes and formal standards, often in professional or scholarly domains.