When an adverb is used to modify an adjective alone (a noun does not follow the adjective), it's called an adjectival phrase.
Example:
The soup is very hot.
- the adverb 'very' modifies the adjective 'hot';
- the adjectival phrase is functioning as a predicate adjective (also called a subject complement) following the linking verb 'is'.
When an adverb is used to modify the adjective that's describing the noun, it's called a noun phrase.
Example: She's wearing a very pretty dress.
- the adverb 'very' modifies the adjective 'pretty';
- the adjectival phrase 'very pretty' describes the noun 'dress' forming the noun 'phrase';
- the noun phrase 'a very pretty dress' is functioning as the direct object of the verb 'wearing'.
