1. someone who prefers to be or work alone
it's hard to get to know him/her as he/she is a bit of a lone wolf
A 'lone wolf' is someone who would rather work on tasks or projects on their own, sometimes because they prefer not to share the credit for a positive outcome. Although being a team-player is seen as a good quality in the business world, many people who rise to the top have done so because they have distinguished themselves from others. This is often what a 'lone wolf' achieves. You might hear this used in social situations, but it is mostly suited to professional contexts.