regressive tax
tax imposed in such a manner that the tax rate decreases as the amount subject to taxation increases
en-US/ɹɪˈɡɹɛsɪv ˈtæks/
en-GB/ɹɪˈɡɹɛsɪv ˈtæks/
tax imposed in such a manner that the tax rate decreases as the amount subject to taxation increases