pentagon
parallelogram
square
a trapezium
parallelogram
A trapezoid has 4 sides, 2 acute and 2 obtuse angles, and only one pair of parallel sides
a diamond does. There are two obtuse angles in it.
A parrelellegram
a diamon, pentagon, nonagon, heptagon
A parallelogram or a rhombus
this shape would be a rhombus
A trapezoid perhaps?
E.g. a parallelogram. See en.wikipedia.org.