QQ plot explanation The figure shows the Q-Q plot of a theoretical and empirical standardized Normal distribution generated through the $qqnorm()$ function of R statistical tool.

How can I describe the right tail (top right) that does not follow the red reference line? What does it mean when there is a "trend" that running away from the line?
Thank you

Looks like your data has a cutoff at $4$.  You could probably fit the samples you plotted fairly well with a curve such as
$$y = \frac 1 2 \left( x + 4 - \sqrt{c+(x-4)^2} \right),$$
where $c > 0$ is a free parameter that describes the sharpness of the cutoff.  Just by eyeballing the graph, I'd guess that $c \approx 0.1$ for your data.
