Gerundives
Gerundives are adjectives formed from verbs, portandus. They decline like bonus, a, um. They are passive (indeed they are sometimes called future passive participles) and include an implication of necessity.
Therefore:
portandus
necessary to be carried
ad pacem petendam
in order to seek peace (for peace which must be sought)
the gerundive of attraction
If a gerund requires a direct object, it becomes a gerundive instead:
profecti sumus ad Romanos necandos
We set out to kill the Romans (lit. to the Romans needing to be killed)
nullam spem piscis ibi capiendi habemus
We have no hope of catching fish there.
the gerundive of obligation
This is the most frequently encountered use of the gerundive, utilising the implication of necessity:
Carthago delenda est
Carthage must be destroyed.
Spartacus necandus erat
Spartacus must be killed.
If an agent is needed for the verb, it is expressed in the dative:
Caesar nobis necandus est
Caesar must be killed by us (We must kill Caesar).
