Put a snap cap in your firearm of choice, then s-l-o-w-l-y pull the trigger while watching the trigger and your finger. If the trigger moves freely with no effort, that's take-up. Once you feel any resistance on the trigger, it should not move until it breaks. If there is any motion while you feel resistance, that's creep. The amount the trigger moves after it breaks is overtravel.
Take-up is bad, creep is worse, and a LITTLE overtravel is tolerable on a rifle, but undesireable on a handgun.
Take-up is bad, creep is worse, and a LITTLE overtravel is tolerable on a rifle, but undesireable on a handgun.