Was the phrase "timey-wimey" (or time-y wimey) used in Doctor Who, or elsewhere, before it appeared in the script of the 2007 episode "Blink"?
In Doctor Who, the first time was in Blink, yes. At least, in the TV series. There might have been other DW material before that (novels or audio plays), which I missed.
Can't be sure about "elsewhere". I certainly did hear it then for the first time.