How to Form and Translate Latin Infinitive Verbs

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Latin is an inflected language and so the endings of its words change to indicate their use in a sentence. Infinitive forms change from verb tense to verb tense. An infinitive is the form of the verb without person or number; it often represents the bare action of the verb without any other information. Unlike most other Latin verbs, an infinitive can serve as the subject of a sentence.

English Infinitives

To form infinitive forms of verbs in English, the construction uses the word “to” plus the verb. For example:

to love

to go

to speak

Infinitives may be in the present tense such as:

to be

to see

to throw

or they may be in the perfect tense which is formed with the word “to have” plus the past participle of the verb such as:

to have been

to have seen

to have spoken

Infinitives may also be in the passive voice such as:

to be liked

to be seen

to be promoted

Often, the infinitive is paired with another verb in a sentence such as:

Sarah likes to go to the city.

Robert is able to see the stage.

Sometimes an infinitive may function as the subject of a sentence as in:

To walk is healthy exercise.

‘To err is human…’

Latin Infinitives

Latin infinitives function similarly as their English counterparts. The infinitive form of the verb is associated with the second principal part of a verb. Principal parts should always be memorized so that all forms of the verb may be known. For example, the principal parts of the word amo (love) are:

amo amare amavi amatum

The second principal part, amare, is the present active infinitive form of the verb. Infinitives in this form always end in –re. It represents in one word what English needs two words to express (to + verb). Like English, Latin infinitives may be active or passive in meaning such as:

amare (to love)

amari (to be loved)

However, formation of perfect passive infinitives gives Latin students some trouble because of their irregular formation. These infinitives must agree with the subject in gender unlike other infinitives. For example:

laudatus, laudata, laudatum esse

However, Latin study programs usually introduce infinitives in an easy-to-understand manner. Stepping through each anomaly makes it easier for the Latin student to grasp all uses and forms of infinitives.


Infinitives in English follow the form of “to” plus the verb. Latin lacks the word “to” so infinitives are formed through inflections. The second principal part of any verb is the infinitive’s present active form, from which the remaining infinitives may be formed. Luckily, infinitives function similarly in both English and Latin.