What does Amorrhaeus mean in Latin?

Amorrhaeus, a noun, means “an Amorite”.

What is the genitive of Amorrhaeus?

The genitive singular is Amorrhaeī. Amorrhaeus is masculine, second declension.

noun · masculinesecond declension

Amorrhaeus m (genitive Amorrhaeī)

Ecclesiastical[a.morˈrɛː.us]

From Koine Greek Ἀμορραῖος (Amorraîos, “Amorite”) in the Septuagint, from Biblical Hebrew אֲמֹרִי (ʾĂmōrî).

adjectivefirst/second-declension adjective

Amorrhaeus²

Amorrhaeus (feminine Amorrhaea, neuter Amorrhaeum)

Ecclesiastical[a.morˈrɛː.us]

singular
form	masculine	feminine	neuter
nominative	Amorrhaeus	Amorrhaea	Amorrhaeum
genitive	Amorrhaeī	Amorrhaeae	Amorrhaeī
dative	Amorrhaeō	Amorrhaeae	Amorrhaeō
accusative	Amorrhaeum	Amorrhaeam	Amorrhaeum
ablative	Amorrhaeō	Amorrhaeā	Amorrhaeō
vocative	Amorrhaee	Amorrhaea	Amorrhaeum

plural
form	masculine	feminine	neuter
nominative	Amorrhaeī	Amorrhaeae	Amorrhaea
genitive	Amorrhaeōrum	Amorrhaeārum	Amorrhaeōrum
dative	Amorrhaeīs	Amorrhaeīs	Amorrhaeīs
accusative	Amorrhaeōs	Amorrhaeās	Amorrhaea
ablative	Amorrhaeīs	Amorrhaeīs	Amorrhaeīs
vocative	Amorrhaeī	Amorrhaeae	Amorrhaea

From Koine Greek Ἀμορραῖος (Amorraîos, “Amorite”) in the Septuagint, from Biblical Hebrew אֲמֹרִי (ʾĂmōrî).