Definition of "doubtlessly"

doubtlessly

adverb
comparative more doubtlessly, superlative most doubtlessly
1. (sometimes proscribed) Without question; indubitably.
2. (obsolete) Without feeling doubt, without misgivings.
  Quotations
  Some powers diuine, or els infernall, mixtTheir 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.
  c. 1587–1588, [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire, London: Scolar Press, 1973, Act II, scene vi