deep in debt
From Longman Dictionary of Contemporary Englishdeep in debtdeep in debtOWEowing a lot of money → deepExamples from the Corpusdeep in debt• Her husband Peter is dying of cancer and the couple are deep in debt.• Ron and Melanie found themselves out of work and deep in debt.• Besides, Tam was deep in debt to Richie again, and couldn't really afford to go anywhere.• The Charterhouse, also deep in debt, was passed over in silence.• After my surgery, we were deep in debt with doctor bills.