| Noun | 1. | lypressin - an antidiuretic and vasoconstrictor used to treat diabetes insipidus antidiuretic, antidiuretic drug - a drug that limits the formation of urine pressor, vasoconstrictive, vasoconstrictor - any agent that causes a narrowing of an opening of a blood vessel: cold or stress or nicotine or epinephrine or norepinephrine or angiotensin or vasopressin or certain drugs; maintains or increases blood pressure |