feature creep

Feature creep is the gradual expansion of a project's scope beyond its original goals, typically through the accumulation of new features during development.

What begins as a simple product grows increasingly complex as stakeholders request additions: The app was supposed to be a basic timer, but feature creep turned it into a full project management suite.

The term implies the expansion is unplanned and potentially harmful—bloating timelines, budgets, and the final product itself.