Final answer:
The superlative degree of an adjective is formed by adding the suffix -est to the end of the word.
Step-by-step explanation:
When forming the superlative degree of an adjective, the suffix -est is commonly added to the end of the word. For example, the superlative of 'tall' is 'tallest' and the superlative of 'happy' is 'happiest'.
Learn more about Superlative Degree of Adjectives