The definition of two-fisted is having or using both fists.
An example of a two-fisted being is a human.
An example of a two-fisted drinker is someone who drinks alcoholic drinks very quickly, as if using drinking two drinks at a time.
Using or held by both hands.
A two-fisted backhand stroke in tennis.
Characterized by vigor, roughness, or aggression.
Two-fisted frontier justice.
Virile, rowdy, vigorous, etc.
Using both fists (figuratively, hands)