肝胆 (gān dǎn) literally means 'liver and gall bladder'—two closely connected organs in traditional Chinese medicine, where they jointly govern courage, decision-making, and emotional resilience. Because the liver stores blood and the gall bladder stores bile, their healthy coordination symbolizes inner strength and clarity.

In extended usage, 肝胆 carries strong metaphorical weight: it expresses deep sincerity, unwavering loyalty, and fearless honesty—qualities believed to originate from these vital organs. You’ll often hear it in phrases like 肝胆相照 (gān dǎn xiāng zhào, 'liver and gall shining upon each other'), meaning mutual trust and openness between close friends or comrades. It’s a warm, elevated term—not used lightly—and appears frequently in literature, speeches, and heartfelt declarations of commitment.