unblock vs unlock

unblock

verb
  • To free or make available. 

  • To remove or clear a block or obstruction from. 

  • In whist, to throw away a high card so as not to interrupt one's partner's long suit. 

  • To enable communication again, via telephone, instant messaging, etc., with (somebody previously blocked). 

noun
  • The removal of a block or blockage. 

unlock

verb
  • To make available. 

  • To undermine something that has control over a situation; to find a way to counter or oppose. 

  • To configure (a mobile phone) so that it is not bound to any particular carrier. 

  • To undo or open a lock or something locked by, for example, turning a key, or selecting a combination. 

  • To obtain access to something; to meet the requirements of a security or protection system. 

  • To disclose or reveal previously unknown knowledge or potential. 

  • To be or become unfastened or unrestrained. 

noun
  • The act of unlocking something. 

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