Adverbial (adjective)

1. Pertaining to or functioning as an adverb.
2. Relating to or serving the function of an adverb in a sentence.

Origin:

From the latin adverbium meaning "adverb".

Examples:

1. The adverbial phrase "very carefully" modifies the verb "walked".
2. He used adverbial clauses to connect his ideas.
3. An adverbial phrase is a group of words that functions as an adverb.
4. The adverbial form of the adjective "fast" is "fastly" but it is not commonly used.
5. An adverbial can be a single word or a group of words.