tax-free, duty-free, free, tax-exempt, untaxed, nontaxable, unratable, excuse, relieve, privileged, more...

liable, accountable, responsible, subject, obliged

501(c)(3), 501(c)(4), 501(c)(5), 501(c)(6), 501(c)(7), 501(c)(8), 501(c)(, more...

tax, non, partially, benign, certain, lax, less, license, equal, fully, immune

free (from),   not liable,   give a free pass,   free to,   not subject to,   free (of),   not obligated,   not require,   not duty bound,   grandfathered in