What is the difference between an allosteric inhibitor and a noncompetitive inhibitor in terms of their mechanisms of action on enzyme activity?

An allosteric inhibitor binds to a site on the enzyme that is different from the active site, causing a change in the enzyme's shape and reducing its activity. A noncompetitive inhibitor binds to either the enzyme or the enzyme-substrate complex, also reducing enzyme activity but without directly competing with the substrate for the active site.