Verbs tell what happens; adverbs often tell how, when, or where. An adverb is a word that modifies a verb, an adjective, another adverb, or sometimes a whole clause, supplying information about manner, time, place, degree, or frequency.

Many English adverbs end in -ly, but plenty do not: often, very, well, not. Position is flexible compared with adjectives, which is why adverbs can appear at the beginning, middle, or end of a clause with only subtle shifts in emphasis.

Learners sometimes overuse -ly forms or misplace adverbs of frequency. Linguists group adverbs into semantic classes and study how they interact with tense, aspect, and negation. In some languages the same form serves as both adjective and adverb, reducing the need for a separate class.

• Modifier of verbs, adjectives, or other adverbs
• Expresses manner, time, place, degree, or frequency
• Position often more flexible than adjective position
• Not always marked by a distinct ending