Robert Mitchum was a famous actor best known for his roles in film noir classics like "Out of the Past" and "The Night of the Hunter." Some synonyms for Mitchum might include "leading man," "Hollywood icon," or simply "actor." Other possible words that evoke his unique style and persona might include "tough guy," "stoic," and "charismatic." Given the range of roles he played over the course of his career, other potential synonyms for Mitchum might include "drama king," "action hero," or "romantic lead." Ultimately, the many facets of Mitchum's persona make it difficult to pin down a single word that truly captures his essence.