The phrase "to beef up" means to make something stronger, more powerful or more effective. It can refer to adding extra features, increasing in size or strength, improving performance, enhancing capabilities, or making something more robust and durable. The term is often used in the context of physical fitness, where it refers to building muscle mass through weight training exercises; but it can also be applied to other areas such as technology, security measures, business strategies, etc., where it means adding extra resources or capabilities to make something more potent.