Read the definition clause by clause
كُلُّ اسْمٍ
Translation: every noun. The subject here is nouns, not all types of words.
رُكِّبَ مَعَ غَيْرِهِ
Translation: joined with something else in a grammatical construction.
وَلَا يُشْبِهُ مَبْنِيَّ الْأَصْلِ
Translation: and not resembling what is inherently indeclinable.
وَيُسَمَّى مُتَمَكِّنًا
Translation: it is also called mutamakkin.
The remaining slides explain each condition through examples and syntactic analysis.