• 涙なみだ — tears
• 涙ぐなみだむ — to become teary
• 感涙かんるい — tears of emotion
• 血涙けつるい — bloody tears (figurative)
• 落涙らくるい — shedding tears
• 涙腺るいせん — tear gland

The さんずい radical signals water or flowing liquid. The right side (戻 → レイ → ルイ) gives the sound. Together they express “tears” — flowing water under emotion.