An adjective is a word that tells us more about a noun. (By "noun" we include pronouns and noun phrases.)
An adjective "qualifies" or "modifies" a noun (a big dog).
Adjectives can be used before a noun (I like Chinese food) or after certain verbs (It is hard).
We can often use two or more adjectives together (a beautiful young Algerian lady).
the, a/an, this, some, any
Adjective Order beautiful, long, dark brown
richer, more exciting
the richest, the most exciting