"Dead right" is an idiomatic expression used to mean that someone is absolutely correct. It is an emphatic way of saying that an individual's opinion or observation is undeniably true. There are many synonyms for "dead right" that can be used interchangeably depending on the context. Some of these include "spot on," "absolutely correct," "undoubtedly true," "unequivocal," "precisely accurate," "entirely accurate," "thoroughly accurate," "completely accurate," "exactly right," and "100% correct." These synonyms convey the same level of confidence and accuracy as the original phrase, making them excellent alternatives that can add variety to one's vocabulary.