An adverbial modifier is a word, phrase, or clause that modifies a verb, adjective, or another adverb, providing additional information about how, when, where, or to what extent an action takes place. These modifiers help clarify the context of the action, often enhancing the meaning of a sentence. When used correctly, adverbial modifiers can enrich writing by adding depth and detail, but if misplaced or dangling, they can create confusion and ambiguity.