It all depends on what kind of polygon it is. It may have no congruent sides or all congruent sides.
An irregular polygon
A polygon with all congruent sides is a regular polygon.
A polygon with five congruent sides is a pentagon.
A polygon with all sides congruent is a square.
A regular polygon is a polygon with congruent sides and interior angles.
It is an equilateral polygon. It is not a regular polygon. For the polygon to be regular, it is not enough for the sides to be congruent: all the angles need to be congruent as well.
It's equilateral !!! A polygon with all sides congruent is equilateral.
It would be an irregular polygon that has not congruent sides and angles
The majority of polygons would meet these requirements. Polygons with congruent sides are the exception rather than the other way around.
a regular polygon