make up out of whole cloth

make (something) up out of whole cloth

To fabricate something entirely fictional or utterly false and not based on reality at all. A reference to tailors who would falsely advertise garments being made "out of whole cloth," when, in reality, they were pieced together from different cuts. To be honest, I don't believe a word he says—it sounds like he made it up out of whole cloth to me.
See also: cloth, make, of, out, up, whole
Farlex Dictionary of Idioms.

make something up out of whole cloth

Fig. to fabricate a story or a lie. That's a lie. You just made that up out of whole cloth. That's a lie. You just made up that story out of whole cloth.
See also: cloth, make, of, out, up, whole
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • make (something) up out of whole cloth
  • make something of whole cloth
  • out of whole cloth
  • cut from whole cloth
  • cut out of whole cloth
  • made from whole cloth
  • made out of whole cloth
  • whole cloth
  • the (some kind of) gods