The word "un-doubtable" means something that is unquestionable or beyond doubt. There are several synonyms that exhibit the same meaning. These include words such as undeniable, incontestable, indisputable, irrefutable, and unassailable. Each of these words presents a surety that cannot be called into question or challenged. These synonyms can be used interchangeably to convey the same meaning in different contexts. For example, when discussing scientific facts, one might use the word "undeniable" to describe evidence that supports a theory. In a courtroom setting, the word "incontestable" may be used to describe a piece of evidence that cannot be disputed. Together, these synonyms allow for more variety and color in our writing, helping us to choose the perfect word to convey our message.