The different i’rab in Arabic are the grammatical cases of nouns and verbs, which are indicated by suffixes and diacritics:

CaseIndicator
Raf, marfuDammah
Nasb, mansubFatha
Khafd/jarr, makhfud/majrurKasra
Jazm, majzumSukun
I’rab is a consistent set of rules that allows Arabic speakers to identify the subject and direct object of a sentence.