PRESSING QUESTION ABOUT "NO SCRUBS"

I was 5 years old when this song came out. So I really didn't have a good grasp of what the *cOoL KiDs* were saying at the time. If you have any information about this, plz share because I lie awake at night stressing about this.
  1. Okay here's my question:
  2. Did this use of "scrub" exist before this song?
  3. I have always just assumed that "scrub" was already in use in the late 90s when this song came out. But lately I've been digging deeper. Asking the tough questions.
  4. The majority of the lyrics are laying out the definition of the term
    A scrub is a guy that thinks he's fly/ and is also known as a buster/ always talkin bout what he wants/ and just sits on his broke ass
  5. Which makes me think that maybe this was a new addition to the cultural lexicon? Like why else would they spend the whole song just explaining what it is?
  6. Can someone who was not a small child in 1999 please enlighten me?