Well-grounded is a term that describes something that is firmly based in knowledge or experience. Synonyms for well-grounded include credible, believable, reasoned, realistic, factual, rational, and sound. A well-grounded argument or opinion is one that is well-supported, logical, and backed up by evidence. A person who is well-grounded has a strong foundation of knowledge, skills, and experience that allows them to make informed decisions and act confidently in various situations. Well-grounded synonyms can be used interchangeably, depending on the context and the desired tone of the communication. In general, using well-grounded synonyms helps to convey a sense of authority, reliability, and expertise.