Fair dinkum is a popular Australian slang phrase used to mean genuine, honest, or authentic. The phrase originated in the early 20th century and has since become a part of Australia's cultural identity. While fair dinkum is a unique phrase, there are many synonyms that can be used in its place. These include: true blue, real McCoy, honest-to-goodness, bona fide, sincere, and truthful. Each of these synonyms carries a similar meaning to fair dinkum and can be used interchangeably, depending on the context. Whether you're an Australian or just a fan of Aussie slang, these synonyms can help you to add some variety to your language usage.