A payer is the person or company who pays — the one who gives the money. Banks, tax offices, and hospitals use it on forms: they need to name the payer so they know who is responsible. In ordinary talk, people rarely say payer by itself; they say “the person who pays,” or they use a fuller word like taxpayer. It feels official, not friendly. Though actually, you will hear it in set phrases: a slow payer is someone who pays late, and a third-party payer is often an insurance company paying the bill instead of you.