A sparring partner is someone who practices or trains with another person in order to improve their skills. However, there are many synonyms that can be used to describe a sparring partner depending on the context. Some similar phrases include training partner, practice partner, workout buddy, sparring mate, or even gym companion. These synonyms can be used interchangeably to describe someone who helps to push and challenge their training partner to improve faster. While the word "sparring partner" is often associated with combat sports, the synonyms can be used in any context where two people are working together to improve their skills or abilities.