nontaxable

Not subject to being taxed.

[…] It is going to be up to the taxpayer, if they receive a 1099 in any form for a nontaxable event, such as splitting rent among roommates, splitting a dinner bill, or even selling something on eBay for less than you paid for it, to explain to the IRS that the 1099 was received for a non-taxable transaction,” said Mark Luscombe, principal analyst for tax publisher Wolters Kluwer Tax & Accounting.

Anything that is not subject to taxation.