"He speaks the truth, sir. From your point of view, he is only a facsimile, a knockoff, a cheap imitation."
"Thank you, Mister Data."
"Sorry sir, that did not come out quite the way I intended."
A counterfeit, facsimile, or knockoff was the imitation of an item with the intent of passing it off as the real thing, such as currency or other items of value. Such activity was generally considered a crime.
In 2024, the January 21 issue of the Los Angeles Times included an article about counterfeit UHC cards. (PIC: "Watcher")
Harry Mudd's police record in 2266 included his purchase of a space vessel with counterfeit currency. (TOS: "Mudd's Women")
Many unscrupulous individuals had produced fabrications of the Shroud of the Sword over the years, claiming they were authentic. (DS9: "The Sword of Kahless")
In 3191, in the Federation Watch List for Moll, counterfeiting was listed with other crimes that she had committed during her career as a professional criminal. (DIS: "Mirrors")