| Surtax 1. (n.) An additional or extra tax. 2. (v. t.) To impose an additional tax on. Thesaurus Entries assessment, cess, conscience money, contribution, direct tax, duty, graduated taxation, imposition, impost, indirect tax, joint return, levy, progressive tax, separate returns, single tax, supertax, tax, tax base, tax dodging, tax evasion, tax exemption, tax return, tax structure, tax withholding, tax-exempt status, taxable income, taxation, tithe, toll, tribute, withholding tax |