Sens. Kent Conrad (D-N.D.) and Mike CrapoMichael (Mike) Dean CrapoTrump calls for looser rules for bank loans in Dodd-Frank overhaul Week ahead: Lawmakers eye another short-term spending bill Overnight Finance: Trump promises farmers 'better deal' on NAFTA | Clock ticks to shutdown deadline | Dems worry Trump pressuring IRS on withholdings | SEC halts trading in digital currency firm MORE (R-Idaho) introduced the bill in April. Conrad said the bill was a response to one of his constituents, who asked for help getting rid of the word "lunatic," language that Conrad agreed is "inappropriate" to have in U.S. law, given the modern understanding of mental illness.

"Sen. Crapo and I agree that federal law should reflect the 21st-century understanding of mental illness and disease, and that the continued use of this pejorative term has no place in the U.S. Code," Conrad said back in April.

The word "lunatic" appears in Title 1, Chapter 1 of the U.S. Code, which covers rules of construction. Chapter 1 holds that when determining the meaning of any law, "the words 'insane' and 'insane person' and 'lunatic' shall include every idiot, lunatic, insane person and person non compos mentis."

According to Conrad's bill, the word also appears in laws related to banking that deal with the authority to take receivership of estates.