The word flush has several meanings:

1. To clean something by running water through it. When you flush a toilet, water rushes through to wash everything away. Plumbers might flush pipes to clear out debris, and doctors sometimes tell patients to flush a wound with clean water to remove dirt.
2. When your face turns red, usually from embarrassment, anger, or physical effort. After running hard in gym class, you might feel flushed, with your cheeks red and warm. Someone caught in an embarrassing moment might flush bright crimson. The redness happens because blood rushes to your face.
3. When things are perfectly even or level with each other. A flush surface has no bumps or gaps. When installing shelves, you want them flush against the wall, with no space between. A carpenter might make two boards flush so they line up exactly.
4. In card games, especially poker, a flush is a hand where all five cards are the same suit, like five hearts or five spades. It's a strong hand that beats most others.
5. Having plenty of money or resources. When someone feels financially flush, they have extra money to spend. After getting paid, you might feel flush enough to buy that book you've been wanting.