Adjectives Governing Cases

Some Latin adjectives are semantically incomplete until another expression supplies their object or reference point: eager for glory, skilled in law, friendly to a neighbour, worthy of praise. English usually introduces that complement with a preposition. Latin often marks it with a bare genitive, dative, or ablative chosen by the adjective. Unlike the classifying relation covered under Relational Adjectives, this dependent phrase is a complement licensed by a particular adjective.

Two case relations must therefore be kept separate. The adjective itself agrees with its head noun in gender, number, and case; its complement takes a case licensed by the adjective’s lexical meaning. In fēmina perīta iūris, feminine nominative perīta agrees with fēmina, while genitive iūris depends on perīta.

The agreement–government split

Fēmina perīta is one nominative noun phrase. Iūris is not something with which perīta agrees; it names the field of expertise and is therefore genitive.

After cum, the head and adjective become ablative (fēminā perītā), but governed iūris stays genitive. This contrast is an excellent diagnostic: agreement changes with the noun phrase’s syntax, while the complement keeps the case selected by the adjective.

Adjectives with the genitive

The genitive often specifies the domain, object of desire, memory, fullness, or participation associated with an adjective. Common Classical adjectives include cupidus “eager/desirous,” perītus and imperītus “skilled/unskilled,” memor and immemor “mindful/unmindful,” plēnus “full,” particeps “sharing in,” and cōnscius “conscious/aware.” This is lexical government: the semantic grouping helps memory, but it does not predict every adjective.

Cupidus agrees masculine nominative singular with adulēscēns; glōriae is the desired object.

Plural genitive locōrum means “of the places/terrain.” English idiom may prefer “familiar with,” but that preposition does not reveal the Latin case.

Memor is a one-termination third-declension adjective; its nominative form does not advertise the gender of the understood first-person subject. Beneficiī supplies what is remembered.

Plēnus commonly takes the genitive, especially when the complement represents contents. Classical authors also use an ablative with plēnus, partly overlapping with an ablative of means or accompaniment. That alternation is real; it should not be “corrected” into a single absolute rule.

Adjectives with the dative

The dative commonly marks the person or thing toward which a relation, likeness, usefulness, suitability, nearness, or friendliness is directed. Frequent adjectives include amīcus “friendly,” inimīcus “hostile,” similis and dissimilis “like/unlike,” aequālis “equal,” propinquus “near/related,” ūtilis “useful,” noxius “harmful,” and idōneus “suitable.”

Amīcus is predicative and agrees with medicus; dative pauperibus identifies the people toward whom the friendliness is directed.

Neuter nominative ūtile agrees with exercitium. Dative corporī gives the beneficiary or reference point.

Idōneus can take the dative, as here, or ad plus accusative when suitability for an activity or purpose is emphasized: idōneus ad pugnandum “fit for fighting.” The alternatives overlap but organize the complement differently.

Similis occurs with both dative and genitive in Classical Latin. The dative is widespread for resemblance to a person or thing; the genitive is also classical and can be favored by particular authors and constructions. Cicero regularly prefers the genitive with persons but uses either case with things, while personal pronouns normally appear in the genitive (meī, tuī). This is a usage choice, not a difference between “correct” and “incorrect” Latin.

The distinction between adjective and noun can change the case pattern:

In the first clause, adjectival amīcus governs dative Caesarī. In the second, substantival amīcus is a noun, and genitive Caesaris identifies whose friend Marcus was. The meanings can converge, but the syntax is different.

Adjectives with the ablative

The ablative often supplies a standard, respect, endowment, content, or cause. Especially important are dignus and indignus “worthy/unworthy,” contentus “content,” praeditus “endowed,” frētus “relying on,” vacuus “free/empty,” and sometimes plēnus “full.” Many of these combinations preserve an instrumental or separative logic.

Honōre is ablative with dignus. English “of” often suggests a genitive to learners, but English prepositions do not map reliably onto Latin cases.

The ablatives name qualities with which the orator is endowed. Masculine nominative praeditus agrees with orātor across both complements.

Neuter ablative parvō is used substantivally, “with a small amount.” Plural contentī agrees with the plural subject understood from the verb.

The ablative reflects separation: fear is what is absent. Vacuus may also take a genitive, especially for contents or lack, so dictionary and corpus evidence should guide advanced composition.

Position, attribution, and predication

The adjective and complement form a semantic unit even when their words are separated. Both attributive and predicative uses are ordinary.

The marked separation is possible in (formal/literary) prose because agreement links cupidus with iuvenis and parallel genitives complete cupidus. Neutral learner prose would more often keep glōriae cupidus together.

Feminine nominative idōnea is predicated of nāvis; dative marī states what the ship is unsuitable for. Position does not make idōnea agree with the nearer neuter-looking form.

Some complements can be omitted when context supplies them: perītus est “he is experienced,” dignus est “he is worthy.” Omission does not turn the adjective into a different part of speech; it leaves an understood semantic argument.

Production checklist

1. Choose the adjective that expresses the intended relation.
2. Look up its attested case pattern; do not infer it from the English preposition.
3. Inflect the adjective to agree with its head noun.
4. Put the complement in the case governed by the adjective.
5. Check whether the adjective also allows an alternative construction and whether that alternative changes emphasis.

The lexical step cannot be skipped. Latin’s case inventory is systematic, but the distribution after individual adjectives is partly arbitrary and must be learned with the adjective.

Common Mistakes

1. Making the adjective agree with its complement

2. Translating English “of” as a genitive after dignus

3. Replacing a governed dative with an English-style preposition

4. Forcing one case onto an attested alternation

5. Matching the adjective to the nearest noun

Key Takeaways

An agreeing adjective and its governed complement belong to different case systems inside the same phrase. Genitives often mark domain or object, datives a target or reference point, and ablatives a standard, endowment, or separation—but each adjective’s attested construction must still be learned. Parse agreement first, then assign the complement case.