Your non romantic male soul mate. Usually when a girl is deprived of a brother this male ends up being the replacement. They are as close as siblings and he means the world to her. He is referred to as the "guy best friend"usually when the girl has best friends who are mostly girls. While most of the time these two remain best friends despite media constantly saying it turns out to romance, it is usually the male that tends to fall for the female. Females who do fall for their guy best friend usually keep it quiet in fear of losing their best friend. People often joke that the two will get married when both honestly find no romantic interest in the other.
Guy: Rose hangs out with Victor way too much to not like him.
Girl:I talk to Rose all the time, she says that he's just her guy best friend. She has no feelings for him whatsoever.