Extremely busy (with something); deeply or overly involved (in something); possessing, filled up with, or overwhelmed by an excessive amount (of something). There's no way I can take a vacation right now, I'm up to my ears in work at the moment! I only meant to be peripherally involved in David's business venture, but before I knew it I was in up to my ears! Dana was worried she wouldn't find any work as an accountant working for herself, but she's up to her ears in clients!

Having too much of something; overwhelmed by something. We're still unpacking our new house, so we're just up to our ears in boxes. If any of my guys get hurt at the construction site, I'll be up to my ears in paperwork.