An adverb is a word that is used to modify a verb, an adjective, another adverb or a word group, and is used to express place, manner, circumstance and degree. Here are a few examples of an adverb: She walks quickly (the adverb is quickly and it modifies the verb walks). She walks extremely quickly (the adverb extremely modifies quickly which is another adverb).
She is an extremely quick walker (the adverb extremely modifies quick which is an adjective). Note: To easily understand adverbs, if it modifies a verb, it commonly tells us how, when, where, in what manner or to what extent a specific action is performed. For example: How – He moved quickly, When – He moved yesterday, Where – He moved there, In what manner – He moved shoeless, and to what extent – He moved steadfast.