high, low
direct, indirect
flat
basic-rate, higher-rate (both BrE)
progressive, redistributive
regressive
A regressive tax takes proportionately more of a poor person's income.

stealth (BrE)
windfall
a windfall tax on the profits of the last few years

back (informal)
The tax office demanded £80 000 in back taxes.

council (BrE), poll (esp. BrE)
federal, local, national, state
capital, capital gains, death (AmE), dividend (AmE), estate (AmE), income, inheritance, land, payroll, profits, property, social-security, wealth
consumption, luxury, purchase (BrE), sales, value added (= VAT)
personal
company (BrE), corporate, corporation
car, road (BrE), vehicle
It's time to renew your car tax.

carbon, energy, fuel, gas (AmE), gasoline (AmE), petrol (BrE)
excise, import
environmental, green

pay
owe
charge, impose, introduce, levy, put
Direct taxes could only be levied with the consent of Parliament.
The government may put an indirect tax on books.

collect
the government department responsible for collecting taxes

deduct
Your employer will deduct the tax for you.

calculate
increase, put up, raise
cut, keep down, lower, reduce
abolish, repeal
eliminate
overpay
claim back, reclaim (BrE)
offset sth against, set sth off against, write sth off against (all BrE)
Claims for expenses can be set off against tax.

avoid, escape
evade
She was charged with conspiracy to evade taxes.

go up, increase, rise
Taxes look set to rise again.

come/go down, fall
be chargeable (BrE), be payable
the amount on which capital gains tax is payable

payer (usually taxpayer)
a higher-rate tax payer

preparer (AmE)
authority/authorities, man (usually taxman), office
She owes the taxman £10 000.

law, legislation, measures, package, policy, reform, structure, system
season (AmE)
April is tax season.

year (BrE)
The tax year begins in April.

cut, reduction
hike, increase
band (BrE), bracket, code, rate, threshold
Her salary puts her in the highest tax bracket.

dollars, money, receipts, revenue, yield
collection
assessment, form, return
You have to fill in your tax return by tomorrow.

advantage, allowance, benefit, break, concession, credit, exemption, incentive, perks (BrE), rebate, refund, relief, saving
There are tax advantages to working freelance.
You will only receive tax relief on the first $30 000.

deduction
affairs, arrangements (both BrE)
His tax affairs are under investigation by the police.

records
preparation (esp. BrE)
avoidance
loophole
Her accountant was good at exploiting tax loopholes.

shelter
dodge, evasion, fraud
He gave the Porsche to his mother as a tax dodge.

dodger
exile (esp. BrE)
She is living as a tax exile in Monaco.

haven
The island is a popular tax haven for the very rich.

assessor (AmE), collector, consultant, inspector (BrE)
bill, charge, payment
arrears (BrE)
He was ordered to pay £2 million in tax arrears.

liability
an increase in tax liability on company cars

burden
He was criticized for putting a new tax burden on the poor.

base
By broadening the tax base (= making more people pay tax) the chancellor could raise more revenues.

after tax, before tax
Profits after tax were $562 000.

in tax
Collectively, smokers pay over £15 000 a day in tax.

tax on
to introduce a 60% tax on alcohol

for tax purposes
He is non-resident for tax purposes.
the rules for deciding on someone's residence status for UK tax purposes

the rate of tax
an increase in the basic rate of tax

inspector of taxes (BrE)

heavily, highly
Many self-employed people are heavily taxed.
goods which are most highly taxed

lightly

according to
Drinks would be taxed according to their alcoholic strength.

at
Many goods were taxed at 17.5%.

on
You will be taxed on all your income.

Tax is used with these nouns as the object:
dividend, earnings, patience