A muddler is a bartender's tool, used like a pestle to mash—or muddle—fruits, herbs and spices in the bottom of a glass to release their flavor.

Why does muddle mean?

: to think or act in a confused aimless way She muddled along for a year before going to college.

What does it mean when a drink is muddled?

Muddling is a technique used in drinks to gently mash herbs or fruit to release their juices. This helps the flavors to bind with the alcohol better than simply using them whole. Muddling is used in many popular cocktails, like the Mojito and Whiskey Smash.