1. an additional tax imposed on top of a regular tax

1. to impose an additional tax on something

Examples

• The government imposed a surtax on luxury goods to raise additional revenue.
• High earners faced a 10% surtax on income above $500,000.
• The city council voted to surtax commercial properties in the downtown area.
• Companies complained about the new environmental surtax on carbon emissions.
• The temporary surtax was designed to fund emergency infrastructure repairs.
• Parliament decided to surtax imported vehicles to protect domestic manufacturers.