Genitive of Friendship

Yeah, I made that genitive up, but only to describe a real phenomenon in Latin! Some adjectives of likeness, nearness, and belonging that normally take the dative will occasionally take a possessive genitive. This transition is especially common where the adjective approaches the force of a noun.

  • Fuit hōc quondam proprium populī Rōmānī: this was once peculiar to the Roman people. (~a peculiar trait of)
  • Fuit semper amīcus Cicerōnis: he was always friendly with Cicero. (~a friend of)
  • Adeō patris similis es: you’re just like your master. (~a chip off the old block)

Here’s the full list of adjectives that perform this function—

  • aequālis,  aequāle: of the same age (~a contemporary of)
  • affīnis, affīne: related to by marriage (~kinsman of)
  • aliēnus, -a, -um: belonging to another (~a stranger to)
  • cōgnātus, -a, -um: fellow-born (~kinsman of)
  • commūnis, commūne: common to (~kinsman of)
  • cōnsanguineus, -a, -um: sharing a bloodline (~kinsman of)
  • contrārius, -a, -um: opposite (~the opposite of)
  • dispār: unlike (dispar suī, in philosophical diction)
  • familiāris, familiāre: of close relation (~intimate of)
  • fīnitimus, -a, -um: adjoining (~neighbor of)
  • inimīcus, -a, -um: hostile to (~enemy of)
  • necessārius, -a, -um: connected with (~component of)
  • pār: equal to (~a match)
  • pecūliāris, pecūliāre: personal (~peculiar trait of)
  • propinquus, -a, -um: neighboring (~neighbor of)
  • proprius, -a, -um: personal (~peculiar trait of)
  • sacer, sacra, sacrum: holy (~holy with respect to some deity)
  • similis, simile: alike to (~spitting image of)
  • superstes: surviving (~survivor of)
  • vīcīnus, -a, -um: neighboring (~neighbor of)

Note that this genitive construction is actually more common for proprius, -a, -um than the dative construction.

Similis with the genitive is especially common with personal pronouns (meī, tuī, suī) and within the fixed phrase vērī similis (probable).

I-Stems: Ablative -ī [6/8]

We see that -im and tend to be common in the same words. That is, where -im is of frequency, so too is .

  • For more on where the -im ending shows up, see this post.
  • Beyond the contents of that post, the -ī ablative ending also appears:


1. with secūrī
2. with the adjectives (nominative -is) where these are used as nouns:

  • aequālī (a contemporary)
  • annālī (annals)
  • aquālī (washbasin)
  • cōnsulārī (former consul, member of the consular rank)
  • gentīlī (relative)
  • molārī (millstone)
  • prīmpīlārī (chief centurion)
  • tribūlī (fellow tribesman)

(As adjectives proper, they would be aequāle, annāle, etc. in the ablative.)

3. in the ablative of i-stem neuters (animālī, baccārī, etc.)


1. With the following nouns: avis, clāvis, febris, fīnis, īgnis, imber, lūx, nāvis, ovis, pelvis, puppis, sēmentis, strigilis, turris (definitions)

2. With the following adjectives (nominative -is or -ens) where they are used as substantives:

  • affīnī (son-in-law)
  • bipennī (battle-ax)
  • canālī (pipe)
  • familiārī (immediate family member)
  • nātālī (birthday, anniversary)
  • rīvālī (rival, competitor)
  • sapientī (wise man)
  • tridentī  (trident)
  • trirēmī (trireme)
  • vōcālī (vowel, vocalist (pl.))

(As adjectives, they would be affīne, bipenne, etc.)

Apparent Exceptions—

  1. The ablative of famēs (hunger) is always famē (not famī nor fame)
  2. The case defective māne (morning) is sometimes mānī (the word is found only in the ablative).
  3. Canis (dog) and iuvenis (youth) always take the ablative -e, never . (contrast with avisclāvis, etc.)