Gradability is a matter of sense rather than a fixed property of a word. This means that, while one sense of an adjective can be gradable, the other can be ungradable.

Generally, adjectives that fall within a spectrum of a quality are considered gradable, while those that are at the end of the spectrum are not gradable because they cannot show any higher or lower degree of that quality. Take a look at the following table to explore some gradable and ungradable adjectives with close meanings:

Most adjectives express a meaning which can be present in a higher or lower degree; these are called 'gradable adjectives'.
Gradable adjectives represent a point on a scale. Thus, we can make comparative and superlative forms from all gradable adjectives. For example, 'cheap' and 'expensive' are adjectives on the scale of 'how much something costs'. Some of the other adjectives in this group include:

Gradable adjectives can be made stronger using a group of adverbs of degree called intensifiers, such as:

Many adverbs can be used to modify gradable adjectives. Among them, 'very' is the most commonly used. But there are other, less common adverbs that can add variety to language use. Take a look at these examples:

Gradable adjectives can usually be made weaker using mitigator adverbs, such as:

Here are some examples:

We can use the structure "be + not + very/that + adj" or "be + not + adj. + at all" to weaken gradable adjectives. Note that this structure is informal and should not be used it in formal contexts.

Other adjectives represent a quliaty which is at the extreme end of a spectrum and cannot easily be made stronger or weaker. These are called 'ungradable adjectives'. Some of the common ungradable adjectives in English include:

The meaning of ungradable adjectives indicates the extremes of a scale; therefore, we cannot use intensifiers and mitigators to modify them. Additionally, many of these adjectives are not traditionally used in comparative and superlative structures. Take a look at these examples:

Instead, emphatic adverbs, which show an extreme degree are used with these adverbs. For example:

Here are some examples:

Ungradable adjectives are not usually used in comparative and superlative degrees. However, in informal English, we can use them comparatively to compare similar things at one end of a scale:

There's also another group of adjectives that show an absolute degree and are not gradable. These adjectives show a binary quality, where something is either one or the other. These adjectives are also modified by the emphatic adverbs and are typically not comparable. Here are some examples: