Infinitives

The infinitive forms of the Latin verb are often neglected in beginning Latin courses. Given the incredible number of constructions in Latin that use the infinitive form of the verb, it deserves your full attention! How many infinitives are there in Latin?

Think for a minute....

There are six of them. Really! And you need to be perfectly familiar with five of them (the future passive infinitive is both weird and rarely found).

Here are the infinitive forms of "tego" ("I cover"), which has for its principal parts: tego, tegere, texi, tectus.

Present Active Infinitive: You learn this form when you learn the main parts of the verb. This is the second principal part of the verb. Each of the four conjugations has its own distinctive present active infinitive ending: -are, -êre, -ere, and -ire.

Present Passive Infinitive: You learn this form when you learn the main parts of a deponent verb, since the deponent verb has only passive forms. Each of the four conjugations has its own distinctive present passive infinitive ending: -ari, -eri, -i, -iri.

Perfect Active Infinitive: To form the perfect active infinitive, you just add "-sse" to the perfect stem, which you learn as the third principal part of the verb. There are no separate conjugations in the perfect system: all the perfect active infinitives end in -isse.

Perfect Passive Infinitive: To form the perfect passive infinitive, you simply take the perfect passive participle (which you learn as the fourth principal part of the verb) and use it together with "esse", the infinitive of the verb "to be." NOTE: Very often the "esse" simply falls out, and the perfect passive participle stands alone. Because a participle has gender, number, and case it has to agree in gender, number, and case with the subject of the infinitive: this is usually the accusative case, but see below.

Future Active Infinitive: To form the future active infinitive, you simply take the future active participle (which is formed from the perfect passive participle, the fourth principal part of the verb) and use it together with "esse", the infinitive of the verb "to be." Because a participle has gender, number, and case it has to agree in gender, number, and case with the subject of the infinitive: again, see below.