Introduction

As the similarity of name implies, gerundives and gerunds are linguistically akin and indeed resemble one another very closely (and sometimes exactly). Despite this, their usage differs, though the distinctions are subtle. You will learn to distinguish the forms and to master their constructions most easily if you bear some basic issues in mind:

• First and foremost: gerundives are verbal adjectives, whereas gerunds are verbal nouns. It may help to think of the gerundive as equivalent to the future passive participle;
• since gerundives are adjectives, they decline fully (showing regular 1st/2nd declension endings like bonus, -a, -um throughout); gerunds, conversely, exist only in the neuter singular genitive, dative, accusative, and ablative. Both gerunds and gerundives are most easily identified by the signature letter sequence -nd-, which is attached to the present stem of a verb;
• gerundives do not exist in English; gerunds do. In fact, you will generally use an English gerund to translate a Latin gerundive.

Formation

Here are the gerundives of the five paradigmatic verbs:

Conjugation:	1st	2nd	3rd	3rd -io	4th
Present stem:	ama-	mone-	reg-	cap-	audi-
Gerundive:	amandus, -a, -um	monendus, -a, -um	regendus, -a, -um	capiendus, -a, -um	audiendus, -a, -um

N.B. in the 3rd -io and 4th conjugations there is -ie- before the -ndus. Gerundives decline exactly like bonus, -a, -um.

Usage

Sometimes the gerundive is used simply as any other Latin adjective, in which case it is best treated as a future passive participle. amandus, for instance, could thus be translated (very literally) "about to be loved," but "to be loved" gets the same point across. But when Roman authors used gerundives, the emphasis in not only the futurity, but imminence and perhaps even inevitability. Horace himself (whom we, of course, know fondly as Quintus) is very fond of gerundives used like this in his poems. Here is an example:

cur invidendis postibus.../sublime...moliar atrium?

Why should I toil over a hallway lofty with columns bound to be envied?

Horace's point is not that, if he exerts lots of effort to build a fancy house, it will cause envy, but that it is bound to cause envy. The emphasis lies not on establishing a time-frame, but upon the probable or even inevitable effect. He could have used a simple adjective invidiosis, which would be translatable as "enviable," but that would not get across the idea that if you build ostentatiously, somebody is sure to feel envy. As you can see, gerundives bring us firmly into the realm of "nuance" and connotation rather than ordinary denotation.

Here's another example, again from Horace's Odes; I have simplified and abridged it for purposes of clarity:

compescit Geryonen Tityonque tristi unda enaviganda omnibus, sive reges sive inopes coloni erimus.

He imprisons Geryon and Tityos with that gloomy stream bound to be navigated by us all, whether we will be kings or peasants.

Horace refers here to Pluto, king of Hades, who uses the River Styx as a sort of security barrier to keep sinners (Geryon and Tityus were two of those eternally punished) in the underworld. But his main point in this sentence is that everybody, rich or poor, is bound to cross that same river--in other words, everyone has to die, regardless of social status. The gerundive enaviganda conveys both the futurity and inevitability of this sad fact with an economy that English cannot manage.

(A) ad + gerundive

A favorite construction in Latin features ad + noun in accusative + gerundive agreeing with accusative, used to indicate purpose (it is, therefore, roughly equivalent to ut + subjunctive).

Quintus rure manebat ad carmina componenda.

Quintus was remaining in the country for the purpose of composing poems.

In connection with this example, please note especially:

• ad + gerundive = "for the purpose of"
• the noun carmina is object of the preposition ad; hence it is in the accusative
• the gerundive--acting like an adjective--agrees with carmina in gender, number, & case
• WE TRANSLATE THIS LATIN GERUNDIVE PHRASE WITH AN ENGLISH GERUND

The last point bears repeating. If we tried to translate the Latin into English more literally, we'd get this: "Quintus was remaining in the country for the purpose of poems (about) to be written." This has no virtue other than preserving the grammatical relationships among the words in the Latin. It's much better--in fact, it is necessary--to convert the gerundive to a gerund, and make the Latin object of the preposition into the English direct object of the gerund.

(B) Gerundive of obligation

Another favorite constuction joins a gerundive with any form of the Latin verb sum to indicate necessity or obligation. In this construction the gerundive agrees with the subject of the sentence, and if there is an agent indicated, it goes into the dative case without a preposition. For example:

Karthago delenda est.

Carthage must be destroyed.

N.B. the participle agrees with the subject; est is present indicative

 

haec officia perficienda erant.

These duties had to be done.

N.B. "had to" because erant is imperfect.

 

Quintus putat imperatorem quasi deum omnibus colendum esse.

Quintus thinks that the emperor must be revered as a god by everyone.

N.B. the gerundive of obligation is part of indirect statement, so you have the infinitive esse.

When translated literally, gerundives of obligation are necessarily passive in voice. If one has a dative of agent, it is possible to rearrange it in translation to make it active, as follows:

haec tibi facienda sunt.

These things must be done BY YOU.

i.e.,

YOU must do these things.

The dative of agent (IN CAPS) becomes subject, the passive verb (in boldface) is made active, and the subject (in italics) becomes direct object.