Irregular is the best word.
It can by rectangular, square, circular, an ellipse or any irregual shape.
It can be flat (plane or 2-dimensional) or be uneven.
ellipse
plane
A straight edge
Ray
a ray
Point
As a point
A point
F is not a geometric shape that is used. The standard geometric term vertex means the intersection point of two sides of a plane figure. If F is meant to represent figure this term might apply.
We generally use the term perimeter to describe the distance around a geometric figure.
Smooth
A geometric term is a term of geometry.
Since there is no way to know what F is, it is impossible to place a geometic term to the object. There are various geometric terms which may apply to objects depending on their structure.
Which geometric term describes a ruler