1. To move or hang about languidly, idly, or lazily. My brother was supposed to be at work, but I found him muddling around down by the river with a friend of his. Once you get the ball, you can't just muddle around behind your offensive line—you've got to act quickly, or those linebackers are going to tackle you!
2. To work or perform in a very mediocre, ineffectual, or unsuccessful manner; to fail to perform to the best of one's abilities. You were such a bright student and talented writer—it kills me to see you muddling around in some office job. The economy had a brief surge after the election, but it has been muddling around at a flat level for the last several months.
3. To dabble in something; to do something sporadically or experimentally. I've been muddling around with different writing styles, trying to find one that suits the stories I'm trying to tell. They haven't changed the core design of the car in decades, only ever muddling around with minor details like the wing mirrors or bumpers.
4. To fumble around awkwardly or clumsily. I didn't want to wake anyone up by turning on the lights, so I had to muddle around in the dark when I came home. I hate muddling around with touch screens—I miss having cell phones with actual buttons you had to press!
to work inefficiently. I can't get anything done today. I'm just muddling around. Jed is not doing his job well. He is muddling around and getting nothing done.