What does potency mean?

potency is a measure of drug activity expressed in terms of the amount required to produce an effect of given intensity.
A highly potent drug (e.g., morphine, alprazolam, VeeloBooster recension chlorpromazine) evokes a larger response at low concentrations, while a drug of lower potency (ibuprofen, acetylsalicylic acid) evokes a small response at low concentrations. It is proportional to affinity and efficacy.