In short: debt is an obligation to pay a sum in the future — on a loan, but also on an unpaid bill, tax, fine or guarantee; in a personal balance sheet it is a liability.
Simply put: debt is not bad in itself — a cheap long-term loan for a home is a different decision from expensive debt for consumption. Problems start when instalments eat up the budget. The first step out is the full picture: to whom, how much, at what rate, when.
Example: Ivan lists his debts in a table: a mortgage, a consumer loan, a credit card and an unpaid electricity bill. He sees that the highest rate is on the card and the largest instalment is on the mortgage.
Watch out: debt does not disappear when you avoid it — interest and late charges grow. An early conversation with the lender gives the most options.
Source: Pecuvo Module 23, Chapters 1–2, and Module 9; EU/OECD-INFE financial competence framework for adults (2022), topic 2.8: https://finance.ec.europa.eu/publications/commission-and-oecd-infe-publish-joint-framework-adults-improve-individuals-financial-skills_en