Doubtlessly

Common synonyms include: undoubtedly, absolutely, admittedly, beyond doubt, beyond question, by all odds.

adv

adv ·Uncommon ·Advanced level

Definitions

Adverb

1
Without question; indubitably. proscribed, sometimes
"There are doubtlessly more insects than mammals."
2
Without feeling doubt, without misgivings. obsolete
"Some powers diuine, or els infernall, mixt Their angry ſeedes at his conception: For he was neuer ſprong of humaine race, Since with the ſpirit of his fearefull pride, He dares so doubtleſly reſolue of rule."

Adverb

"There are doubtlessly more insects than mammals."

From Middle English doutelesly, dowtelesly, equivalent to doubtless + -ly.