As a Noun: 1. The person you do something with like dancing, playing a game, or owning and running a business. English = partner. 2. A person you know well and like to spend time with. English = mate, friend. As a Verb or Adjective: 1. To do something with someone like dancing, playing a game, or owning and running a business. English = (be) partners. 2. To be best friends with someone, especially while at school, if not ever since school. English = (be) buddies, (be) mates.