A polygon face is non-planar when: it has more than three vertices, and one or more of those vertices do not lie in the same plane.

What does non planar mean?

: not planar : not lying or able to be confined within a single plane : having a three-dimensional quality … there is no way of redrawing this circuit so that none of the elements cross. This, therefore, is an example of a nonplanar circuit.—

What is planar and non planar?

A graph is said to be non planar if it cannot be drawn in a plane so that no edge cross. ... These graphs cannot be drawn in a plane so that no edges cross hence they are non-planar graphs.