The present infinitive is the nominative singular of a verbal noun. The other cases of this verbal noun are provided by the gerund. The supine is a verbal noun whose uses are very much confined. In fact it consists of only an accusative and an ablative form. It is derived from the fourth principal part and takes fourth declension endings.The accusative of the supine is also used in the rare future passive infinitive. The accusative is used with verbs of motion to indicate purpose. It is necessary to differentiate those instances which carry the meaning of an ablative of respect from those which bear the meaning of an ablative of cause. The ablative is used with certain adjectives as an ablative of respect. Only the former may take the supine, while the latter may be a gerund, depending on the context. The supine is best translated as an English infinitive.