To waste something, especially money or time, in a careless or reckless way.
Squander is a bad thing. It means using something in a way that is not smart or careful.
Examples:
He will squander all his money on toys.
Don't squander your time playing video games.
She squandered all her allowance on candy.
I squandered all my snacks on the first day of the trip.
He squandered his whole year's savings on a single meal.
If you squander all your food, you will be hungry later.