What is the meaning of Payer?

One who pays; specifically, the person by whom a bill or note has been, or should be, paid.

A swaption which gives its holder the option to enter into a swap in which they pay the fixed leg and receive the floating leg.

to pay (for)

to pay (someone)

to buy (something)

pay for (suffer the consequences of something)

to pay off (to be fruitful)

to pay

to pay

Source: wiktionary.org