What does it mean to do something in vain?
vain Pronunciation: ‘vAn Function: adjective Etymology: Middle English, from Anglo-French, empty, futile, from Latin vanus — more at WANE 1 : having no real value : IDLE, WORTHLESS
Doing something “in vain” means that you do something that has the same outcome as if you had not done it. (For example, people say that someone has died in vain if they were fighting to change something and after they died, whatever it was they were fighting for, never changed. Or if you love in vain it may mean that you love someone who has done something wrong and you believe that if you love them enough, they will change. You go on to love that person and they do not change. It can be said you loved them in vain.