Nulli secundus is a Latin phrase that translates as "second to none." It denotes the superiority or excellence of an individual or something else. There are several synonyms that can be used instead of nulli secundus. For instance, " unparalleled" means that nothing else compares to the subject in question. "Unrivaled" can also be used instead of nulli secundus. "Incomparable" and "matchless" are other synonyms that can be employed. Additionally, "peerless," "superior," and "unequaled" are perfect alternatives to nulli secundus. All these words indicate that the subject in question is the best and there's nothing that can match its standards.