What does wagering mean?

You don't know what "wager" means? And you are betting? Wager means betting.

Yes, you probably need to bet 60x the 25 before you can withdraw. You don't need to deposit 1500 into the site, you just need to make that amount of bets. You make a 25 bet with what's in there and win. Now you have 50. Make another 10 wager and lose.... now you have 40. But you've made a total of 35 in bets. If you still have a balance after 1500 worth of bets, then withdraw it if you want.

It's supposed to be a risk free chance at making money? Well, did you put any money into the site? No? Then it's risk free, obviously.

Most people will join the site, lose that 25, and then put money in and lose it. Some might see how long the free money lasts and then never go back. The amount of people that never put anything in and manage to win is very small. They aren't dumb.

I will admit, this is a first, to have someone ask what "wagering" means after joining a gambling site.

If you don't know what a wager is, why are you on a casino website at all?

It means you have to make 1500 in bets prior to withdrawing that money.