1. without doubt; certainly; undoubtedly
Usage: formal or literary register; often used to emphasize confidence in a statement

Examples

• She will doubtlessly succeed in her new role given her experience.
• The team is doubtlessly the strongest competitor in the tournament.
• He doubtlessly knew the answer but chose not to speak.
• This discovery will doubtlessly change our understanding of the disease.
• You are doubtlessly aware of the recent policy changes.
• The project will doubtlessly require additional funding.