The phrase 臭味相投 is formed by combining the characters 臭 (smell), 味 (taste), 相 (mutually), and 投 (to agree or harmonize), where the nominal compound 臭味 (odors and tastes) functions as the subject and the verbal phrase 相投 (to mutually align) as the predicate, creating a literal meaning of "smells and tastes are in harmony".