Yes, understating your income when reporting it to the IRS (for taxes) is fraud.
However the situations being discussed are credit/loan applications. Since understating your income in that application doesn't generally provide any material benefit, there would be no "element of actual or attempted pecuniary gain"
However the situations being discussed are credit/loan applications. Since understating your income in that application doesn't generally provide any material benefit, there would be no "element of actual or attempted pecuniary gain"