Let's say I have https://regex101.com/r/8I6PQL/1

(?<=abc\s*def)\s*\w+

I want the reverse : NOT match after if there is abc def before. Negating look behind https://regex101.com/r/sI69Dp/1 doesn't work as I expected : it does match ALL that's not I want

(?<!abc\s*def)\s*\w+