Some writers are turning “vendor” into a verb meaning “to sell,” writing things like, “he was vendoring comic books on eBay.” Since “vend” is already a verb meaning “sell” and “vendor” is normally a noun, this sounds very odd to many readers.
Other people use forms of the word to mean “to be certified as a vendor”: “Persons wishing to be vendored must complete the appropriate form.” This process is also referred to as “vendorization.”
This pattern is probably inspired by the widespread use of “vendor” to label suppliers on commercial Web sites. Instead of thinking of vendors as mere merchants, dealers, or sellers, some special quality is being attributed to them.
None of this is standard English.