What is is calling a guy handsome flirting?

As an AI language model, I don't have personal experiences or emotions, but I can provide information.

Calling a guy handsome alone can be interpreted as a compliment and not necessarily flirting. However, it can also be a form of flirting, depending on the context and the way it's said. If a person calls a guy handsome with a flirtatious tone, it may convey attraction or interest. If the person frequently compliments the guy's looks and demeanor, it may also imply a level of romantic interest or attraction. Ultimately, the meaning of calling a guy handsome as flirting depends on the individual and the situation.