• IPA: /ˈdaʊ̯tləs/
• (Canada) IPA: /ˈdʌʊ̯tləs/

doubtless (not comparable)

1. Characterized by or experiencing no doubt at all, certain; undoubted; undoubting.
   • 1880, B. Stewart and P. G. Tait, The Unseen Universe, Macmillan (London), p. xiii:

     There are those who have doubtless faith in revelation.

2. (obsolete) Free from fear or suspicion.
   • c. 1596, William Shakespeare, “The Life and Death of King Iohn”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: Printed by Isaac Iaggard, and Ed[ward] Blount, published 1623, OCLC 606515358 ↗, [Act IV, scene i]:

     Pretty child, sleep doubtless and secure.

• German: zweifelsfrei, zweifellos
• Russian: несомне́нный
• Spanish: indudable, sin duda

doubtless (not comparable)

1. Without doubt; very probably, in all likelihood; doubtlessly.
   • 1893, Ambrose Bierce, "The Realm Of The Unreal":

     I cannot remember that I spoke a word, though doubtless I did.

   • 1900, L. Frank Baum, The Wonderful Wizard of Oz:

     The men, Dorothy thought, were about as old as Uncle Henry, for two of them had beards. But the little woman was doubtless much older. Her face was covered with wrinkles, her hair was nearly white, and she walked rather stiffly.

• indubitably, undoubtedly, unquestionably, without a doubt, indisputably

• French: sans aucun doute, sans nul doute, indubitablement
• German: zweifellos
• Spanish: indudablemente