To encroach means to gradually intrude or advance into a space or area where you don't belong, often in a way that slowly takes over. When a forest encroaches on an old field, trees and bushes slowly spread into the open space year after year. When one country's army encroaches on another's territory, it pushes forward bit by bit into land that isn't theirs.

The word often describes something unwelcome that creeps in gradually rather than arriving all at once. Development might encroach on wildlife habitats as new houses are built closer and closer to where animals live. At your desk, a messy classmate's papers might encroach on your workspace, spilling over the invisible boundary between you.

You can also use encroach when talking about rights or freedoms. If a new rule encroaches on students' free time by requiring extra study hours, it's taking away something that belonged to them. The key idea is that encroachment happens gradually and crosses a boundary, whether that boundary is physical (like property lines), personal (like your space), or more abstract (like rights or time). Unlike a sudden invasion, encroachment is a slow advance that can go unnoticed until it has already claimed significant ground.