إعراب means something like analyze, it is one of the aspects of the Arabic grammar and morphology.
I-irab is which you analyze a whole sentence it's one of the reasons why the Arabic grammar is very difficult.
example:
أعرب/أعربي الجملة التالية. أكلَ يوسفُ التفاحةَ
جملة فعلية(لأنها بدأت بفعل
أكل: فعل ماضي مبني على الفتح
يوسف: فاعل مرفوع وعلامة رفعه الضمة
التفاحة:مفعول به منصوب وعلامة نصبه الفتحة
this is a very simple example of I-irab but it's very difficult and unnecessary to learn, native Arabs would need to study 4-7 years in college to fully understand it, for me I suck in Arabic grammar big time but I don't make mistakes at least not many
this is a the wiki I-irab link:
ʾIʿrab - Wikipedia, the free encyclopedia
the one who developed the Arabic language was the great scholar Sibawayh he was the best scholar of the Arabic language, he also was a Persian.