SURTAX
surtax, supertax
(noun) an additional tax on certain kinds of income that has already been taxed
surtax
(verb) levy an extra tax on; “surtax luxury items that cost more than $1,000”
Source: WordNet® 3.1
Etymology
Noun
surtax (plural surtaxes)
(legal) An additional or extra tax.
Verb
surtax (third-person singular simple present surtaxes, present participle surtaxing, simple past and past participle surtaxed)
(transitive) To impose a surtax upon.
Source: Wiktionary
Sur"tax, n.
Definition: An additional or extra tax.
Sur*tax", v. t.
Definition: To impose an additional tax on.
Source: Webster’s Unabridged Dictionary 1913 Edition