Novillero is a Spanish word that refers to a young bullfighter who is still mastering the art of fighting bulls and is yet to reach the professional level. There are several synonyms for the word novillero such as novato, aprendiz, becerrista, neófito, principiante, tientero, and subalterno. All these words denote a similar meaning, that is, a beginner in the art of bullfighting who is still learning and refining his skills. These synonyms can be used interchangeably depending on the context and the tone of the conversation. However, it is important to note that each of these words has its unique connotation and nuance in the world of bullfighting.