First, let’s begin with the definition of each. An adjective is any word that modifies a noun and generally answers the questions, "What kind of?" or "Which one?" For example, in the sentence, "I saw a spotted dog" spotted is the adjective because it modifies dog, thus answering the question of "What kind of dog?"

An adverb is any word that modifies a verb, an adjective or even another adverb, and generally answers the questions of, "Why?" "When?" "How?" "How much?" For example, in the sentence, "I walked along the shore slowly, searching for shells" the word slowly is the adverb because it answers the question of "How was I walking?"

Although most people think only adverbs end in "-ly," that is not true. There are a number of adjectives that also end in "-ly." Some of these are:

Though these words can be used as adverbs, it is recommended that they be used as adjectives to avoid poorly written sentences. For example, instead of writing, "Mary treated me motherly" it is better to simply insert a phrase and write, "Mary treated me like a mother."

In addition to having adjectives which do end in "-ly," there are adverbs that don’t. These are generally short adjectives that, under certain conditions, can be used properly as an adverb. Some of these are:

For example, "He did fine" uses the word "fine" as an adverb because "fine" answers the question of "How did he do?" This sentence reads much better than "He did finely" which puts the familiar "-ly" on the end of the adverb.

When you do use an adjective or an adverb, let your ear be your guide. If you are unsure about whether or not to add "-ly" to that adverb, say both forms aloud. Chances are you’ll hear the correct one.

However, use adjectives and adverbs sparingly. These words will weaken your writing. Whenever possible, use a stronger verb or noun form instead. For example, instead of writing, "I walked along slowly," try "I crept along." Of course, the verb or adverb choice does come down to the feel you are trying to give in each scene.