Join Fight Meaning Enter Military Order Train Member

Meaning: If you join up, you enter the military in order to train and become a member of one of the armed forces.

• join up Johnny wants to join up and fight in Iraq, but his mum doesn't want him to risk his life in a war she doesn't support.
  
  
• join up If you join up, you'll have to fight and kill whoever the government tells you to, even if you don't think it's right.