What is the opposite of obligated?

voluntarily
at will

suggestive or not requisite

deobligated

non-obligated

irresponsible / unaccountable

Not obligated.

free

Unencumbered

non-obligated , not obligated.

irrefutable, unaccountable, unprovable, freed, unbound, ungrateful
blameless, excused, exempt, irresponsible, let off the hook, unaccountable, unreliable, untrustworthy
just to name a few