Sight Unseen Meaning

(idiomatic) Not having seen the object beforehand.

Example: 1902, Myrtle Reed, Lavender and Old Lace, ch. 5:
  When she wrote, asking me to take charge of her house while she went to Europe, I gladly consented, sight unseen.
2005 Aug. 2, Michiko Kakutani, "They'll Take Manhattan, for a Million or More," New York Times (retrieved 1 Sep. 2008):
  More than $300 million worth of condominiums were sold in the new Time Warner complex sight unseen while the building was still under construction.