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Synonyms

doubtless

American  
[dout-lis] / ˈdaʊt lɪs /

adverb

  1. without doubt; certainly; surely; unquestionably.

  2. probably or presumably.


adjective

  1. free from doubt or uncertainty; certain, sure.

doubtless British  
/ ˈdaʊtlɪs /

adverb

  1. certainly

  2. probably

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

adjective

  1. certain; assured

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Related Words

Doubtless, undoubtedly, indubitably, unquestionably are adverbs that express certainty. Doubtless, although it sometimes denotes an absolute degree of certainty, more often means “probably,” “presumably,” or “no doubt”: She will doubtless accept the offer. Undoubtedly means “beyond doubt”: undoubtedly the most prolific and popular composer of his time. Indubitably and unquestionably both affirm an unassailable conviction; they differ only in tone, indubitably being appropriate to more formal or learned discourse and unquestionably appropriate in a wider range of contexts and styles: an indubitably (or unquestionably) accurate transliteration of the hieroglyphic text; unquestionably the hottest running back in the league.

Other Word Forms

  • doubtlessness noun

Etymology

Origin of doubtless

First recorded in 1300–50, doubtless is from the Middle English word douteles. See doubt, -less

Explanation

Use the adverb doubtless to mean "absolutely" or "without question." You could tell your brother that he'll doubtless be thrilled about the birthday present you got for him. You might rule out several neighborhoods when you're looking for a new apartment to rent, knowing they'll doubtless be too expensive for you. When she invites you to dinner, your friend might warn you about her dad's long stories, adding, "He'll doubtless tell you the one about his trip to Europe during college." Doubt is at the heart of doubtless, from the Latin dubitare, "to doubt, question, or hesitate."

Keep Reading on Vocabulary.com

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

That is one element of this which the committee is doubtless going to want to probe further, and perhaps where Sir Olly felt on shakiest ground.

From BBC • Apr. 21, 2026

South Korean missile defenses now operational in the United Arab Emirates have doubtless attracted attention in both Iran and North Korea.

From The Wall Street Journal • Mar. 17, 2026

Come 2028, there will doubtless be many Democrats seeking to replace President Trump.

From Los Angeles Times • Feb. 25, 2026

But he will doubtless hope to continue a post-season in which refereeing decisions have largely been uncontroversial -- with one major exception.

From Barron's • Feb. 3, 2026

In fact, the manner in which his intended bride’s family reacted to the discovery of it was doubtless the first and last time when the Sutpen family ever surprised him.

From "Absalom, Absalom!" by William Faulkner