fettered vs unbound

fettered

adj
  • Of the feet: bent backward and apparently unfit for walking. 

  • Bound by chains or shackles. 

  • Restricted. 

unbound

adj
  • Not bound; not tied up. 

  • Without a binding. 

  • 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. 

How often have the words fettered and unbound occurred in a corpus of books? (source: Google Ngram Viewer )