Adjectives and adverbs, the two kinds of modifiers or describing words, can be distinguished from each other by the kinds of things they describe. Adjectives describe things, and adverbs describe action or other describing words.
Adjectives are describing words that answer the questions "what kind of thing?" or "which thing?"
Examples (the italicized words are adjectives):
Not all adjectives are just one word. Notice the multiple-word adjectives in the following sentences: