why do i have a half moon by a name in my messages

You have set the message in question to Hide Alerts. It is like a Do Not Disturb. If you swipe the message slightly to the left, you will see the Hide Alert icon. Tap on it, and it should remove the half moon icon.

That means that Hide Alerts is turned on for that message thread. Slide that message to the left and tap the bell shaped icon to turn alerts back on.