unbound

Adjective

unbound (not comparable)

1. Not obligated.
   • Near-synonyms: unconstrained, unrestrained, unencumbered; unfettered, fetterless
   • The terms of the contract inadvertently left certain unbound aspects to subjective interpretation.

   Synonyms:

   unconstrained, unrestrained, unencumbered, unfettered, fetterless

2. Not tied up.
   • Near-synonyms: unfettered, fetterless, unrestrained, unchained, unshackled, shackleless, unmanacled, unhandcuffed
   • The hostages' hands were left unbound.

   Synonyms:

   unfettered, fetterless, unrestrained, unchained, unshackled, shackleless, unmanacled, unhandcuffed

3. Without a binding.
   • an unbound book
   • Beneath an old ebony table were two long carved oak chests. I lifted the lid of one, and at the top was a once-white surplice covered with dust, and beneath was a mass of tracts — Commonwealth Quartos, unbound — a prey to worms and decay.1880, William Blades, The Enemies of Books, page 40
4. (nuclear physics) Lying beyond the proton or neutron drip line; having a negative particle separation energy; capable of decaying by the spontaneous exothermic emission of one or more nucleons.
   • Helium-2 is unbound, as it is energetically favorable for it to split into two separate protons.