Tajrīd contains a particular kind of intensification: it conveys the perfection of a trait through a second, imagined bearer emerging from the original. Not all intensification is tajrīd.
“He is extremely generous” intensifies a quality without extracting another figure. “His generosity could yield another generous man” uses the extractive conception and thus resembles tajrīd.
Tajrīd names the mechanism of extraction. The succeeding topic, al-mubālaghah al-maqbūlah, separately examines acceptable exaggeration and its degrees. These are not synonymous categories.