definitely

Defi nitely is an adverb that expresses certainty or without doubt. It signals a strong affirmation and can modify verbs, adjectives, or entire clauses. In conversation it is used to convey confidence or commitment, as in “This plan will definitely work,” or as a one-word response, “Definitely.”

The word is formed from the adjective definite with the adverbial suffix -ly. It is commonly pronounced with three syllables: DEF-i-nit-ly, though in rapid speech speakers may say something closer to DEF-nit-lee. The pronunciation remains stable across major varieties of English.

Usage notes indicate that definitely is more common in informal and spoken registers. In formal writing, alternatives such as certainly or undoubtedly may be preferred. It can carry a tone of enthusiasm or strong assurance, so writers choose it when a higher degree of conviction is intended. Overuse can make statements seem exaggerated or insincere, especially in careful or cautious discourse.

Common errors include misspelling and confusion with similar-looking words. A frequent misspelling is “definately.” The word “defiantly” is a different term meaning in a rebellious or resistant manner, not certainty. Distinguishing these helps maintain clear communication. Examples: “The plan will definitely succeed” versus “The plan will definitely succeed, if conditions hold,” and “They acted defiantly,” not “definitely.” See also certainty-related terms such as certainly, undoubtedly, and unquestionably.