What is the word for use of an adverb to modify adjective that results in reiteration adjective?

There isn't a specific, single word that perfectly captures the use of an adverb to modify an adjective resulting in a reiteration of the adjective. However, there are several terms and concepts that describe this phenomenon:

1. Intensification: This is the most common and general term. It encompasses adverbs that amplify or strengthen the meaning of an adjective.

* Example: "He was extremely tired." (The adverb "extremely" intensifies the adjective "tired.")

2. Emphasis: This is similar to intensification, but focuses on the emphasis placed on the adjective.

* Example: "She was incredibly beautiful." (The adverb "incredibly" emphasizes the adjective "beautiful.")

3. Redundancy: This term applies when the adverb and adjective express essentially the same meaning, resulting in a somewhat unnecessary repetition.

* Example: "It was very obvious." (The adverb "very" adds little to the meaning of "obvious" and could be considered redundant.)

4. Pleonasm: This is a more formal term for redundancy. It describes the use of more words than necessary to express an idea.

* Example: "The clear and evident truth." (The phrases "clear" and "evident" convey the same meaning.)

5. Intensifying Adverb: This is a more specific term that directly refers to the type of adverb used to modify the adjective.

* Example: "She was absolutely stunning." (The intensifying adverb "absolutely" enhances the adjective "stunning.")

Ultimately, the best term to use depends on the specific context and the effect you wish to achieve. While some examples might be considered redundant, others can be used for emphasis or to create a more emphatic tone.