What is the difference between an adjective and an adverb?

One way to remember the difference between an adjective and an adverb is that adverb has the word verb in it. Since a verb is a doing word or action, an adverb describes an action whereas an adjective describes a noun. If this is hard to remember in an exam, you can remember that adverbs usually (though not always) end with "ly".
Example sentence: "She happily shook the tall man's hand."If you are asked to find the adjective and the adverb in this sentence, you can tell that happily is the adverb because it describes a verb. Or, if you're stuck, you can tell that it is the adverb because it ends in "ly". This means that the other describing word, tall, is an adjective, because it describes a noun.