An approach to building software in short cycles with frequent feedback, instead of planning everything up front and delivering once at the end. Scope, priorities, and estimates are revisited as the team learns.
Requirements almost always change once real users see the product. Agile makes that change cheap: you discover the wrong assumption in week three, not after six months of invisible work.
We work in one- or two-week cycles with a demo at the end of each. You see working software continuously, reprioritise between cycles, and can stop or redirect the project at any boundary without losing the work already delivered.