Windfall
Also called: lump sum, unexpected money
A windfall is a large one-off sum — inheritance, settlement, bonus, sale of a business, lottery win. The consistent research finding is that windfalls are spent faster and less carefully than earned income, because we mentally file them in a separate, looser account. The standard defence is a deliberate delay: park the money somewhere boring and insured for 60–90 days, decide nothing, and use the interval to work out tax owed, which is the most common windfall mistake.