The word stall has several meanings:

1. To stop working or moving, usually suddenly. When a car stalls, its engine quits running, often at the worst possible moment, like at a traffic light. An airplane can stall when it loses the airflow it needs to stay aloft. A conversation might stall when nobody knows what to say next.
2. To delay something on purpose, buying yourself more time. A student might stall when called on in class, saying “um, well, let me think...” while trying to remember the answer. Someone might stall getting their homework started by sharpening pencils, organizing their desk, or getting a snack. Parents can usually tell when kids are stalling at bedtime with requests for one more story or one more glass of water.
3. A small compartment or space, like a bathroom stall with walls and a door, or a market stall where someone sells vegetables or crafts. A horse stall is where a horse sleeps in a barn.

When you're stalling, you're not moving forward. Sometimes stalling happens by accident, like when an engine quits. Other times people stall deliberately, hoping circumstances will improve or that they'll think of a better solution if they wait a little longer.