[1] The origin of the term can be traced to the term "code smell" which was featured in the book Refactoring: Improving the Design of Existing Code by Martin Fowler.
It is a good practice to identify design smells in a software system and apply appropriate refactoring to eliminate it to avoid accumulation of technical debt.
The context (characterized by various factors such as the problem at hand, design eco-system, and platform) plays an important role to decide whether a certain structure or decision should be considered as a design smell.
Generally, it is appropriate to live with design smells due to constraints imposed by the context.
Nevertheless, design smells should be tracked and managed as technical debt because they degrade the overall system quality over time.