A male
friend who is your right-hand man. He's usually there for you, and is there to support you, and is very good at doing so in social situations. He's always there to offer you a wing.
The term originated from it's usage in aviation, and was then used to refer to a man who would help his friend get his target
woman. The wingman would distract the target
woman's friend while his friend went in for the target.