prodrug A substance which, after metabolic action in the body, is coverted to an active drug. prodrug drug modified by biotransformation (i.e. metabolic processes) to achieve desired pharmacological action proÂ·drug (prÅ'drÅ­g) A class of drugs, the pharmacologic action of which results from conversion by metabolic processes within the body.
verb (used without object), sagged, sagging. 1. to sink or bend downward by weight or pressure, especially in the middle: The roof sags. 2. to hang down unevenly; droop: Her skirt was sagging.
Definition of snag for Students. 1  1 : a rough or broken part sticking out from something. 2  2 : an unexpected difficulty Our plan hit a snag. 3  3 : a stump or stub of a tree branch especially when hidden under water.