What situation is called over-development in a weather report?

Question

Question PPL(H) - Private Pilot License - Meteorology

QuizVDS · Accepted Answer

Vertical development of Cumulus clouds to rain showers

QuizVDS · Answer

Development of a thermal low to a storm depression

QuizVDS · Answer

Widespreading of Cumulus clouds below an inversion layer

QuizVDS · Answer

Change from blue thermals to cloudy thermals during the afternoon

Id 371 - PPL(H) EN - What situation is called "over-development" in a weather report?