boss up verb 3exclamation 1forms 3 verb3 •(slang) To strive to reach one's goals through effort and determination; to start working hard.When life gets you down, boss up and take control. •To modify a corner in sheet lead to avoid leaving a hole in the angle. •(old-fashioned) To manage a household and its servants. exclamation1 •(South-Africa, no longer used) Take care; look out. formsbossed up · bossing up · bosses up