Using several words with similar meaning does not make things more clear or accurate.

• "completely, accurately, and sufficiently" - what is the requirement for the domain model? It has to accurately represent the domain entities right? Having something described "Completely" can be also not acceptable if one just needs to represent the data "sufficiently". So, using several words here is missleading.
• "ambiguity, variability, and misinterpretation" - In the given context all of these three words, can be seen as synonims. They are however used as being complementary. This is missleading.

Existing Wording:

Overfitting occurs when there is more extensive expressivity in the data model than is required to completely, accurately, and sufficiently represent domain entities and concepts within the information carrier (data model) resulting in ambiguity, variability, and misinterpretation.

Proposed Wording:

Overfitting occurs when there is more extensive expressivity in the data model than is required to accurately represent domain entities and concepts within the information carrier (data model) resulting in ambiguity and leading to misinterpretation.