Definition of man up:
°to "be a man about it"; to do the things a good man is traditionally expected to do, such as: taking responsibility for the consequences of one's actions; displaying bravery or toughness in the face of adversity; providing for one's family, etc.
"I was wondering when he would man up and marry that girl he knocked up."
°(of military personnel in a unit) to assemble, each person manning (attending to) his station, prepared for departure of an aircraft, ship, etc.
Definition of man up:
°to "be a man about it"; to do the things a good man is traditionally expected to do, such as: taking responsibility for the consequences of one's actions; displaying bravery or toughness in the face of adversity; providing for one's family, etc.
"I was wondering when he would man up and marry that girl he knocked up."
°(of military personnel in a unit) to assemble, each person manning (attending to) his station, prepared for departure of an aircraft, ship, etc.