It likely means “he isn’t six-five” — with “six-five” referring to a height of 6 feet 5 inches, so the phrase is saying the person is not that tall.

What it means

In casual internet slang, people often use numbers like “six five” to talk about height. So “er ist nicht six five” is a mixed German-English phrase that most naturally reads as “he is not 6'5”.

Why it sounds odd

The German part “er ist nicht” is normal German for “he is not,” but “six five” is English, not German. That mix is common in memes, captions, or comment sections where people switch languages for effect.

Possible context

  • A joke about someone’s height.
  • A reply correcting an exaggerated claim.
  • A meme-style phrase with no deeper meaning beyond “not that tall.”

Cleaner German

If someone wanted to say it fully in German, they might say:

  • Er ist nicht 1,96 m groß.
  • Er ist nicht 1,95 m groß.
    depending on the exact height they mean.

Bottom line

It’s basically a height joke or correction: “he’s not 6'5.”