Is gambling OK? Don't bet it! There's not an easy or instantly obvious proof text answer to that question.
In my own perception gambling is not a sin its only an entertainment to refresh yourself,it is a kind of relaxiation in your mind to free from worry and recreation yourself awareness.the only sin if you gambling with cheat in your bet,or your behavior of how to handle in gambling by making debt even if you have no more money or asset,or maybe you betting all your properties to gain your loss and that is what we could a sin.
In some religion gambling is consider as a sin, So it will be consider as sin if you even playing it for entertainment or enjoyment. If you are putting money there then you are comitting a sin. But still in some religions it is not consider as a sin. In my religion gambling is consider as a sin.
If its considered as a sin by your religion's standards, then don't gamble. Of course for most people, religion weighs a lot more than their vices and its better even if your religion prohibits you from gambling. It saves you from the demise it will bring financially