- 信誓旦旦 xìnshìdàndàn to vow solemnlyto make a solemn pledge; to promise with the utmost sincerity; often used to describe a couple's vows of love and loyalty
- 旦旦而伐 dàndàn'érfá to wear oneself outto chop (trees) every day; a metaphor for continuous destruction or the gradual ruin of one's physical health (often through dissipation or excess)