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Webster 1828 Edition

adv.

Boldly; courageously; honorably.

manfully ‎(comparative more manfully, superlative most manfully)

In a manful manner; with the characteristics considered typical of a man, such as strength, courage, and determination.
- From The Adventures Of Tom Sawyer by Mark Twain
  One (ant) struggled manfully by with a dead spider five times as big as itself in its arms.
- From The Bertrams by Anthony Trollope, p.264
  She manfully struggled on, however - womanfully would perhaps be a stronger and more appropriate word. She had to calculate not only how to play her own hand correctly, but she had to calculate on her partner's probable errors.