Also, full of the devil. Mischievous, naughty. For example, The youngsters were full of it today, giving the teacher a hard time, or Bill is full of the devil, hiding his roommate's clothes and teasing him mercilessly.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.