Pyrrolidine, also known as tetrahydropyrrole, is an organic compound with the molecular formula (CH₂)₄NH. It is a cyclic secondary amine, also classified as a saturated heterocycle. It is a colourless liquid that is miscible with water and most organic solvents. It has a characteristic semen-like odor. Compared to acyclic secondary amines, it is about 10 times more basic.