nonfiler means one who neglects to file a tax return. Lexicurio rates it Sui generis — a strength score of 85 out of 100.
Etymology
From non- + filer.
noun
- One who neglects to file a tax return.“Ms. Olson added that despite promises and the creation of a high-level committee, the I.R.S. had failed to enact policies that would bring more nonfilers into the system.”