Technical debt is the cost of your management shortcuts compounded with interest.
It is a fancy term to try to explain to the management that bad long term technical decisions were made and that now they need to bank for it.
Often management is responsible for the technical debt, sometime it is a shared responsibility with the technical staff sometime it is a mix of both – in any case – whatever this is – it will always have a cost to fix it – and a cost to not fix it – which is greater is really the main question.
General assumption is that the more you wait to fix it, the more the cost of not fixing it will outgrow the cost of fixing it.
Fixing means sometime to spend a day to rewrite some part of the system, or a week, a month, a year… depending how much you waited and how much work there is to do to fix it.
Non exhaustive list of stuff about technical debt
Open Technical Debt
Technical debt 101 by Maiz Lulkin
A primer about technical debt, legacy code, big rewrites and ancient wisdom for non technical managers
Technical Debt is Risk Management
Last but not least :
Why management wants more technical debt