The simplest definition of an adjective is that it is a word that describes or clarifies a noun. Adjectives describe nouns by giving some information about an object's size, shape, age, color, origin or material.
English grammar can be tricky, there are often exceptions to the rules, so you need to be careful. You'll find that English adjectives often end with these suffixes:
If you come across a word that ends in -y, -ary or -ate (or any other suffix for that matter), and you want to know if it's an adjective, just look at where it is and what it's doing in the sentence. If it comes immediately before a noun, and especially if it comes between an article (a, an, the), a possessive adjective (my, his, her, its, your, our, their), a demonstrative (this, that, these, those) or an amount (some, most, all, a few) and a noun, then it's an adjective.
Adjectives also act as complements. Complements are words that complete the predicate of a sentence when the verb is "be."
When you list several adjectives in a row, there's a specific order they need to be written or spoken in. Native speakers of English tend to put them in the correct order naturally, but if you're learning English, you'll have to memorize the order. It goes like this:
This is the correct order for adjectives that come directly before a noun, and they are separated by commas.
If the adjectives come after the verb "be" as the complement, then the qualifier (the defining word) will stay with the noun at the beginning of the sentence. The adjectives in the complement are separated by commas with the final two being separated by "and."
Adjectives add information and interest to your writing but more adjectives do not necessarily make a better sentence. Use them wisely.