Competitive inhibition is a process in biochemistry where a molecule, known as an inhibitor, competes with a substrate for binding to an enzyme's active site. This means that when the inhibitor is present, it can block the substrate from attaching to the enzyme, preventing the enzyme from catalyzing its reaction. This type of inhibition can be overcome by increasing the concentration of the substrate. As more substrate molecules are available, they can outcompete the inhibitor for the active site, allowing the reaction to proceed. Competitive inhibition is important in regulating metabolic pathways and can be a target for drug design.