The generation of an ML model that corresponds too closely to the training dataset, resulting in a model that finds it difficult to generalise to new data.

ISO/IEC TR 29119-11:2020 generation of a ML model (3.1.46) that corresponds too closely to the training data (3.1.80), resulting in a model that finds it difficult to generalize to new data

ISTQB - CTAI Syllabus The generation of an ML model that corresponds too closely to the training dataset, resulting in a model that finds it difficult to generalize to new data (After ISO/IEC TR 29119-11)