The word "undefeatable" means "unbeatable" or "invincible". It is an adjective that describes something or someone that is incapable of being defeated or overcome in a fight or competition. Although there may be some subtle differences between the words "undefeatable" and "invincible", both generally convey the idea of something or someone that is extremely strong and difficult to be defeated. In other words, the word "undefeatable" is often used as a synonym for "invincible" and suggests a strength or ability that is nearly unattainable or incomparable.
It seems like you're not reading things correctly, Seth. Do you have a vision problem? Why don't you try seriously counter-arguing each image below?
Look at you bragging because Xebec is possibly stronger than a 15-year-old Kaido apprentice? However, Xebec was never placed above Prime Kaido.
Who's next? Roger? Roger died and was executed during a period when Kaido possibly didn't reach his peak strength. Furthermore, there is information in the manga that contradicts the logic of Roger being superior to Kaido, and one of that information is King's statement: "Just keep being the strongest," and this applies to Prime WB, who was seen in later chapters avoiding conflict with Kaido.
Regarding Shanks, Seth, there isn't a single line in all 1084 manga chapters that puts Shanks above Kaido, not even a statement that implies it.