-eius

• -ejus, -eiius, -eijus (orthographic)

By analogy with nomina gentilicia of Oscan or perhaps Etruscan origin, such as Pompeius (from 𐌐𐌖𐌌𐌐𐌄 (pumpe, “five”)), Tarpeius, Saufeius. Difficult to distinguish from Etymology 2.^[1] Gentilics ending in -eius may have originated from a Faliscan variant of this suffix, whereas -aius (as in Anaius, Popaius, Ulaius) may go back to Oscan, and -aeus (as in Annaeus) to Paelignian and Umbrian.^[2]

• (Classical Latin) IPA^(key): /ˈei̯.i̯us/,
• (modern Italianate Ecclesiastical) IPA^(key): /ˈe.jus/,
• Note: although the syllable is heavy due to the regularly geminate intervocalic /j/, the vowel is thought to have been short on etymological grounds.

-eius (feminine -eia, neuter -eium); first/second-declension suffix

1. forms nomina gentilicia

   ‎Elatus → ‎Elateius

   ‎Proculus → ‎Proculeius

• This suffix was also used to form humorous words such as sterteia (“one who snores”) from stertō (“snore”) by Petronius and sterceia (“a maidservant who cleans the excrement of children”) from stercus (“dung, manure”) by Tertullian.

• -uleius

Derived adjectives from nouns and names with an -ē stem with the suffix -ius (such as plēbēius (“of the common people”) from plēbēs (“the common people”), an archaic form of plēbs). Difficult to distinguish from Etymology 1.

• (Classical Latin) IPA^(key): /ˈeː.i̯us/,
• (modern Italianate Ecclesiastical) IPA^(key): /ˈe.jus/,
• Note: the vowel is thought to have been long on etymological grounds.

-ēius (feminine -ēia, neuter -ēium); first/second-declension suffix

1. forms adjectives from nouns and proper names

   ‎pāgus + ‎-ēius → ‎pāgēius

From Ancient Greek adjectives in -ήϊος (-ḗïos), Epic form of Attic -εῖος (-eîos). Perhaps more properly considered a poetically variant scansion of the suffixes under Etymology 1 and 2, modelled on the corresponding situation in Greek.

• (Classical Latin) IPA^(key): /ˈeː.i.us/,
• (modern Italianate Ecclesiastical) IPA^(key): /ˈe.i.us/,
• Note: this suffix is trisyllabic.

-ēĭus (feminine -ēĭa, neuter -ēĭum); first/second-declension suffix

1. (literary, poetic) Forms adjectives, chiefly from Ancient Greek nouns, but occasionally from native ones as well

   ‎Ancient Greek φῠ́λλος (phúllos, “leaf”) → ‎Phyllēĭus (corresponding to Φῠλλήϊος (Phullḗïos))

   ‎Ancient Greek Πρῐ́ᾱπος (Príāpos) → ‎Priāpēĭus (corresponding to Πρῐᾱπήϊος (Priāpḗïos))

   ‎Tiberius → ‎Tiberēĭus