To postpone is to delay an event or occasion until a later time, usually due to circumstances beyond control like the weather. Postpone can also mean to put something in a position of less importance.
Ex: The city had to postpone its Christmas parade because of dangerous travel due to a snowstorm. Officials hope that the roads will be better next weekend.
Postponing something implies that the event will be rescheduled. Sometimes, an event is postponed indefinitely. In that case, it is not likely to be rescheduled. Postponing the inevitable is a figurative use of postpone. It means that you are delaying something that's going to happen anyway.
Ex: When Linda let all the others in her life¬saving class go before her to perform CPR on a live person, she was just postponing the inevitable. She would have to perform CPR eventually to get her certificate.
To keep away from something or someone is to avoid it. It also means to prevent from happening or refrain from doing something.
Ex: I avoided breaking my leg when I fell by twisting my body to one side. I could not avoid the bruises I got on my hip and shoulder.
Ex: I avoided doing my homework as long as I could, but my mother sat me down at the table in the kitchen and watched me while I completed it.
The expression, avoid like the plague, means that you find something or someone extremely unattractive or threatening. You might avoid your neighbor like the plague because he always wants to borrow your tools.
Ex: Even though she craves it, Beth avoids chocolate like the plague. It always makes her skin break out and gives her a rash.
Ex: When the elders of the village imposed punish Jonah for his bad behavior, the other members of the village started avoiding him like the plague.