The phrase 'action speaks louder than words' suggests that what people do is more significant and revealing than what they say. It emphasizes the idea that intentions and beliefs are best demonstrated through actions rather than mere verbal expressions. For instance, someone may claim to support a cause, but their true commitment is revealed through their active participation and contributions. This concept highlights the importance of integrity and authenticity, as actions can validate or contradict spoken words, ultimately shaping perceptions and trustworthiness in personal and professional relationships.