Free; frank.
"He spoke freely about his mistakes during the team meeting."
In a free manner.
"The birds flew freely across the open sky without any barriers."
The word freely comes from the Old English frēolīc, which originally described someone as freeborn or noble before evolving into its current adverbial form. It entered Middle English through a combination of the root for "free" and a suffix meaning "-ly," shedding its earlier connotations of glory to simply mean without restriction.