Concept: Technical Debt
What exactly is technical debt? Everyone seems to have a different answer. If you ask a developer or manager, you're going to get different interpretations. How about, learning the meaning from the source?
Ward Cunnigham is the original inventor of the term and to put it shortly, he describes it as below:
...The natural result of writing code about something we don't have a proper understanding of...
It is basically a disagreement between business needs and how the software has been written.
Here is a great article explaining technical debt in detail: https://refactoring.fm/p/the-true-meaning-of-technical-debt