up to one’s knees
up to (one's) knees
1. Literally, in some substance, such as water or mud, to the level of one's knees. The water was so cold that I only went in up to my knees. We found ourselves up to our knees in filthy muck as we made our way through the marsh.
2. Having more than one wants (of something). A: "Will you buy this old TV off of me?" B: "No thanks, we're up to our knees in these old units as it is." You're up to your knees in books—why do you keep buying more?
3. Very busy (with something); deeply involved or engrossed (in or with something). I'd love to come for a pint, but I'm up to my knees with work for my class on Monday. John has been up to his knees with the kids lately.
up to one’s knees
mod. deep in something, such as paperwork or water. (see also knee-deep in something.) We’re up to our knees with orders and getting more all the time.