Scope creep refers to a project that has seen its original goals expand while it's in progress. As the term suggests, scope creep is a subtle process that starts with small adjustments and ends up resulting in projects that take far longer to complete or even fail before they are finished. Even if the project is completed, scope creep can result in final deliverables that look nothing like what was originally envisioned.
Scope creep may also be called creep of scope.
Techopedia explains Scope Creep
Scope creep can occur for a number of reasons, including:
A poor understanding of the original project
Changing market conditions
Competing forces within a company
To avoid the worst kinds of scope creep, a project manager should consider even minor adjustments to the original project scope carefully and rework time lines, provide new estimates and communicate with the stakeholders before integrating changes. This should filter out all but the most important concerns.