"Red-blooded" is an adjective that is often used to describe people who are robust, vigorous, or passionate. Some potential synonyms for this term might include words like hearty, hearty, robust, vigorous, hearty, zealous, passionate, fiery, or strong-willed. Other possibilities might include words such as bold, brave, courageous, daring, fearless, or valiant. Ultimately, the specific synonym that one might choose for "red-blooded" will depend on the context of the sentence or phrase in which it is used, as well as the writer's individual style and voice. Nevertheless, there are myriad potential options available to anyone seeking a suitable alternative to this popular adjective.