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Synonyms

doubtless

American  
[daut-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

Synonym Usage

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

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."

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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.

See Examples For:

I should be glad to see all of them retire and succeeded, doubtless, by fresh cliché-mongers.

From The Wall Street Journal ● Oct. 4, 2026

But to offer some differentiation, many will doubtless portray him as being a bit too out there, especially when they start making the electability argument.

From Los Angeles Times ● Sep. 13, 2026

With his new teeth, enjoying Albania's cuisine will doubtless also be part of Anthony's programme.

From BBC ● Sep. 8, 2026

Elon Musk, who knows a little about branding, doubtless would approve of Ms. Super’s ticker change.

From The Wall Street Journal ● Jun. 10, 2026

Thornfield! that, doubtless, was the name of her house: a neat orderly spot, I was sure; though I failed in my efforts to conceive a correct plan of the premises.

From "Jane Eyre" by Charlotte Brontë

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