What is the meaning of stand up?

verb

• Rise to one's feet.
  • usage: "The audience got up and applauded"
  • synonyms: arise, rise, uprise, get up
• Refuse to back down; remain solid under criticism or attack.
• Put into an upright position.
  • usage: "Can you stand the bookshelf up"
  • synonyms: stand, place upright
• Be standing; be upright.
  • usage: "We had to stand for the entire performance"
  • synonyms: stand
• Defend against attack or criticism.
  • usage: "He stood up for his friend"; "She stuck up for the teacher who was accused of harassing the student"
  • synonyms: stick up
• Resist or withstand wear, criticism, etc..
  • usage: "Her shoes won't hold up"; "This theory won't hold water"
  • synonyms: hold up, hold water
• Rise up as in fear.
  • usage: "The dog's fur bristled"; "It was a sight to make one's hair uprise"
  • synonyms: bristle, uprise