胶水 (jiāo shuǐ) is the noun for glue or adhesive — the actual sticky liquid or paste you apply. It's different from 粘 (zhān), which is the verb 'to stick or glue' (the action), and from 胶带 (jiāo dài), which is adhesive tape (a different object). 黏 (nián) is an adjective meaning 'sticky in quality'.