Defer and postpone both involve delay, but they are not always the same in tone or use.
Defer is often more formal. It can mean to delay a decision, action, or event, and it can also suggest yielding to someone else’s judgment or authority. For example, The committee decided to defer the final ruling sounds formal and procedural.
Postpone is the more common everyday choice. It usually means to move something to a later time. For example, We postponed the meeting until Friday clearly means the meeting will happen later.
A useful contrast is this: if you are talking about a schedule, postpone is often the natural word. If you are talking about a formal decision, or about letting someone else decide, defer is often better.
- Defer: formal delay, or yield to another person’s judgment.
- Postpone: general delay to a later time.
- Example contrast: The judge deferred sentencing and The school postponed the concert.
In short, choose postpone for most everyday delays, and use defer when the context is more formal or when the idea of yielding is part of the meaning.