Actually a circular argument is circular. You do argue in circles.
For instance, from Wiki;
Mr. A. "Do you believe in god?"
Mr. B. "YES"
Mr. A. "Why do you believe in god?"
Mr. B. Because it is written in the Bible.
Mr. A. "Why do you believe the Bible?"
Mr. B. "Because the Bible is the word of god"
Or;
"How do you know that it is a 5 million year old fossil?"
"Because it is in a 5 million year old rock". And they defend the age of the rock with that of the fossil.
Or;
"There isn't a problem with the rule, because if everyone obeyed it there wouldn't be a problem."
Why? I'm not going to climb aboard that trolley either. I don't care if gods exist or not because if they exist they apparently don't care about anything here.