“Verbal: A verb form that functions in a sentence as a noun, an adjective, or an adverb rather than as a principal verb. Thinking can be fun. An embroidered handkerchief. (See also gerund, infinitive, and participle.)”
Excerpted from: Strunk, William Jr., and E.B. White. The Elements of Style, Fourth Edition. New York: Longman, 2000.