VERBAL

Definition:
In traditional grammar, a verb form that functions in a sentence as a noun or a modifier rather than as a verb.
Verbals include infinitives, gerunds, and participles (see below for definitions and examples).
Unlike ordinary verbs, verbals are not inflected for person and tense.

Types and Examples of Verbals:

• Infinitives
  Verbals (usually preceded by the particle to) that function as nouns, adjectives, or adverbs.
  "We can only learn to love by loving."
  (Iris Murdoch)
• Gerunds
  Verbals that end in -ing and function as nouns.
  "We can only learn to love by loving."
  (Iris Murdoch)
• Participles
  Verbals that function as adjectives.
  "The eagles swooped and hovered, leaning on the air, and swung close together, feinting and screaming with delight."
  (N. Scott Momaday, House Made of Dawn)

Observations:

• "To write complete sentences, rather than sentence fragments, use verbs or verb phrases, not just verbals. Although a verbal is formed from a verb, it is a part of speech that functions as a noun, adjective, or adverb, not as a verb."
  (Grammar for Writing. Sadlier-Oxford, 2000)
• "Verbals, such as known or swimming or to go, are verb forms that act as adjectives, adverbs, or nouns. A verbal can never serve as a sentence's main verb unless it is used with one or more auxiliary verbs (has known, should be swimming)."
  (Laurie G. Kirszner and Stephen R. Mandell, The Concise Wadsworth Handbook, 2nd ed. Thomson Wadsworth, 2008)
• "Because they are derived from verbs, verbals retain some of the abilities of verbs. They can carry objects or take modifiers and complements. At the same time, verbals possess abilities unknown to the typical verb, the abilities of other parts of speech. In this way, verbals may perform the duties of two parts of speech simultaneously.
  
  "In spite of these new powers, the verbal must give up one of the abilities of its original verb form. No verbal can assume the role of a true verb to express action or condition in a sentence."
  (Michael Strumpf and Auriel Douglas, The Grammar Bible. Owl Books, 2004)