The story
By analogy with man up.
Etymology from Wiktionary, CC BY-SA 4.0.
person up
Today it means: To show courage, strength, toughness, or responsibility; a gender-neutral alternative to "man up". Full definition →
Today it means: To show courage, strength, toughness, or responsibility; a gender-neutral alternative to "man up". Full definition →
By analogy with man up.
Etymology from Wiktionary, CC BY-SA 4.0.