Volitive modality (abbreviated VOL) is a linguistic modality which indicates the desires, wishes or fears of the speaker. It is classified as a subcategory of deontic modality.
Volitive moods are a category of grammatical moods that are used to express volitive modality. Examples are the optative, desiderative and imprecative moods. However, many languages (like English) have other ways to express volitive modality, for example modal verbs ("Would that you were here!", "May he live forever!").
The volitive in Esperanto is really a generic deontic mood, expressing commands as well as will, desire, and purpose. It is formed by adding a -u to the verb stem.