unprecedented
1. [ adjective ] having no precedent; novel
Examples:

"an unprecedented expansion in population and industry"

Related terms: precedented new
Similar spelling:   unprecedentedly
  unpredicted
  unforeseen
  unprotected
  unfrequented
  unappareled
  unpremeditated
  unpretending
  unprejudiced
  unapparent
  unprepared
  unparented
  unforested
  unpresidential
  unforeseeable
  unappreciated
  unpreventable
  unpresentable