1. To fix or fasten something at a high position (on something or some surface) with pins or some similar fastener. A noun or pronoun is used between "pin" and "up." Would you mind pinning up this notice about our upcoming show? I'm pinning posters of my missing dog up all over town. I pinned her signed photograph up on my wall.

2. To fix or fasten something at an elevated position with pins or some similar fastener. A noun or pronoun is used between "pin" and "up." I was feeling lazy, so I just pinned my hair up in a bun and left it at that. We need to pin the curtains up while the carpets are being cleaned.