Gradable / Non-gradable adjectives  There are two kinds of adjectives: gradable and non-gradable.Some adjectives refer to qualities which are gradable – we can have more or less ofthem. For example, people can be more or less interesting or old; jobs can be more orless difficult. Other adjectives refer to non-gradable qualities – we do not say that thingsare more or less perfect, impossible or dead.

So:

Gradable adjectivesThese are adjectives that describe qualities that can be measured in degrees, such as size, beauty, age, etc.They can be used 1) in comparative and superlative forms2) with grading adverbs (such as 'very' or 'extremely' to make it stronger; or weaker: “fairly” cold).3) to show that a person or thing has more or less of a particular quality. Examples: angry, busy, happy, important, big, cold, hot, frightened, kind, nice, expensive, risky, complex, profitable, high, helpful, interesting, difficult.

Non-gradable adjectives (We can use an adverb whch emphasis them, but not an adverb which makes them stronger or weaker.   1) classifying adjectives: these describe qualities that are completely absent or completely present. They do not occur in comparative or superlative forms Examples: chemical, indoor, married, wooden, pregnant, English, useless, green, nuclear, domestic, digital. 

2) extreme adjectives: these are adjectives that mean "very" + adjective Examples: ancient        (very old )amazing      ( very surprising )boiling        ( very hot )brilliant       ( very intelligent )deafening    (very loud)delighted     (very happy /pleased)disgusting   (very bad /unpleasant)excellent     (very good)exhausted  ( very tired )fascinating   (very interesting)filthy            (very dirty)freezing       ( very cold )furious        ( very angry )gorgeous    (very beautiful)starving      ( very hungry)terrifying     (very scary)tiny           ( very small)  3) absolute adjectives: dead, impossible, unique, perfect, supreme, final, correct __________________________________   Look at these pairs of gradable and non-gradable adjectives:

angry / furiousbig / enormousimportant / essentialhot / boilingcold / freezingtasty / delicioustired / exhaustedhappy / delighted

Now why would one want to classify the adjectives? The reason is that it will tell you what adverbs can be used with these adjectives.

 Adverbs of degree: The following adverbs of degree can be used with gradable adjectives: hugely, incredibly, fairly, rather, less, reasonably, a bit, very, really, extremely, slightly. Examples:  very hot, extremely angry,  a bit cold, fairly important And those adverbs of degree can only be used with non-gradable adjectives :  absolutely,completely, really, utterly, totally. Examples: utterly terrifying, really amazing.Different intensifying adverbs go with gradable and non-gradable (limit/extreme)adjectives.With gradable adjectives With non-gradable adjectives

(not) very prettyfairly reallyquite extremelyrather

absolutely reallytotally quitecompletely pretty

Other adverbs often tend to collocate with certain adjectives although these collocations are not exclusive:

Utterly useless, delightful, miserarableHighly skilled, educatedTotally crazy, exhaustedCompletely different, relaxed

Not all combinations are possible (there are no rules!). The only combinations that are always possible are:

very + gradableabsolutely + non-gradablereally + gradable / non-gradable

FAIRLY, QUITE, RATHER, PRETTY

not nice fairly nice quite nice rather/pretty nice very nice

Fairly is the weakest of the four. If you say that somebody is fairly nice, it is notmuch of a compliment.

Quite is a little stronger. If you say that a film is quite good, you are recommendingit: it is not the best film ever made, but it is certainly worth seeing.

Rather is stronger again; it often means more than is usual or more than expected.If a film is rather good, it is better than most. This use is not common in

AmericanEnglish.

Pretty is similar to rather, but it is mostly used in informal style