A rhomboid has which of the following characteristics?

A rhomboid is defined as a type of parallelogram where opposite sides are parallel, and while it retains characteristics of a parallelogram—such as having opposite angles equal—it does not require all angles to be equal. The defining feature of a rhomboid is that opposite sides are equal in length, and only the angles opposite to each other are equal, leading to a lack of the restriction of having all angles equal, as you would find in a rectangle or square.

The option indicating that a rhomboid has opposite sides parallel and only opposite angles equal accurately reflects this definition. Thus, this choice emphasizes the unique form of the rhomboid, distinguishing it from other quadrilaterals, particularly the rectangle, where all angles must be equal.