Tackifier is a sticky substance that helps things like glue, tape, and other adhesives stick better. It's like a special ingredient that makes these things work better. Think of it like adding syrup to your pancakes - it makes them taste better and stay together. Tackifiers work the same way for adhesives. They're made of special chemicals that help the glue stick better to different surfaces, like paper, plastic, or metal. This way, when you stick something together, it stays stuck!