IPA: //ˈtæksˌpeɪər//
KK: /ˈtæksˌpeɪər/
A person or organization that pays taxes to the government.
Every taxpayer is required to file their tax returns by April 15th.
Taxpayer → It is formed from "tax" (from Latin "taxare", meaning to assess or estimate) and "payer" (from Old French "paier", meaning to pay). The word "taxpayer" refers to a person who pays taxes, thus being assessed for their financial contributions to the state.
Think of someone who is 'assessed' ('tax') for their financial contributions and then 'pays' ('payer') those amounts — that's what a taxpayer does.
No commonly confused words.