English adjectives and adverbs usually distinguish three degrees – the positive, the comparative and the superlative. An adjective or adverb in its base form is in the positive degree. Comparative adjectives and adverbs are used to express a higher degree than that is present in something else. The superlative adjectives and adverbs express a maximal degree.

We have already seen that the comparative degree is formed with ‘–er’ or ‘most’. For example, by adding ‘–er’ to the positive adjective ‘tall’, we form the comparative adjective ‘taller’. Similarly by placing ‘more’ before the positive adjective ‘beautiful’, we change it into the comparative form ‘more beautiful’.

The superlative degree is formed with ‘–est’ or ‘most’.

Examples are given below:

Big, bigger, biggest
Small, smaller, smallest
Short, shorter, shortest
Careful, more careful, most careful
Beautiful, more beautiful, most beautiful

Notes
Short adjectives and adverbs form their comparatives and superlatives by adding ‘–er’ and ‘–est’ to the positive. Longer adjectives and adverbs take ‘more’ and ‘most’.

Degree modifiers
Degree modifiers are used to make finer distinctions of degree. A degree modifier is a word used to modify an adjective or adverb. Degree modifiers express the degree to which some quality is present. Examples are: very, too, enough, so, somewhat, rather, moderately etc.

This watch is very expensive.
She is too fat.
It is very heavy.
He is rich enough to buy a car.

In colloquial English, some additional degree modifiers such as pretty, kind of, sort of, bloody etc., are also used.

That watch was pretty expensive.

Traditional grammarians often classify the degree modifiers as a subclass of adverbs.