According to Cambridge Dictionary, an adjective is defined as ‘a word that describes a noun or pronoun’.

According to Collins Dictionary: “an adjective is a word such as ‘big’, ‘dead’, or ‘financial’ that describes a person or thing, or gives extra information about them. Adjectives usually come before nouns or after linking verbs.”

According to Oxford Learner’s Dictionary an adjective is “a word that describes a person or thing, for example ‘big’, ‘red’ and ‘clever’ in a big house, red wine and a clever idea.”

Where do you put them?

Adjectives can occur both before and after a noun:

The blue sea - The sea is blue
The old man - The man is old

Adjectives can come in three positions in a sentence: Attributive, Predicative and Postpositive.