up to the chin in
Used also with "ears", "elbows", "eyes" or "knees" instead of "chin", and with a possessive instead of "the".
1. Having a big or important part in; guilty of; not innocent of; deeply in.
Was Tom mixed up in that trouble last night? He was up to his ears in it.
Mr. Johnson is up to the eyes in debt.
Mrs. Smith is in debt up to her chin.
Compare: TO THE HILT.
2. Very busy with; working hard at.
Bob is up to his neck in homework.
They are up to their elbows in business before Christmas.
3. Having very much or many of; flooded with.
Mary was up to her knees in invitations to go to parties.