The term 'words denoting action' refers to verbs, which are words that express an action, occurrence, or state of being. Verbs are a key part of any language and are used to describe the actions of people, animals, objects, and ideas. Verbs can be conjugated to express different tenses, such as past, present, and future. Verbs can also be modified to express different moods, such as imperative, indicative, and subjunctive.