Dissaving is negative saving. If spending is greater than disposable income, dissaving is taking place. This spending is financed by already accumulated savings, such as money in a savings account, or it can be borrowed. Household dissaving therefore corresponds to an absolute decrease in their financial investments.
Usually dissavings start after retirement, when an individual starts deducting money from the amount that he has been saving during his life time. There are also other reasons for dissavings; like big purchases, huge events, and emergencies. On the macro level, also governments could reach a certain situation where they start dissaving from their accumulated funds.