grep: skip lines containing string x (exclude x)

Using grep, I wanted to skip lines that contained a certain string. I fired up man grep and searched for exclude and skip. No result. Then I hit Google and found instantly: regex - GREP - how could I exclude one word.

So why didn't I find this info in the man file? Because it says:

      -v, --invert-match
            Invert the sense of matching, to select non-matching lines.