WordNet sense 1 (grant relief or an exemption from a rule or requirement to):

free, relieve

WordNet sense 2 ((of goods or funds) not subject to taxation):

nontaxable

WordNet sense 3 (not subject to usual rules or penalties):

privileged

WordNet sense 4 (secure against):

immune

WordNet sense 5 (grant exemption or release to):

excuse, excuse, let off