Nope, in my view gambling is a style of life rather than a hobby. True and abstracted gamblers will bet on everything even on tomorrow's whether and it doesn't matter with whom and where. They are gambling in the sake of process which is part of their psychologic life. I'm not in their class. For me personally gambling is a kinf of "hash-time" session when spending my leisure time.
To be precise, it has a different meaning for different people. Some would consider gambling a part of their lifestyle, some would think of it as a way to earn money, some would say they gamble only for fun, so it's not that it has a single meaning and everyone would consider it that.
Those who consider gambling a hobby might gamble every day when they have free time or extra money, some might even get addicted to it when considering it a hobby because we often see people getting too attached to their hobbies and the things they do regularly.
The best way is to consider gambling a way to have fun and get entertained only when you have money that you can afford to lose.