Final answer:
A government that embodies federalism with limited central authority and a lack of unified support for the common good is described as a confederation.
Step-by-step explanation:
The term that describes a government which follows the principle of federalism, but has a lack of unity and support for the common good, is known as a confederation. A confederation has a weak central authority that is dependent on the consent of the subnational or state governments. This type of government allows for significant self-rule and autonomy within individual states. However, it may lead to a lack of a unified national policy and an inability to address collective needs effectively, which implies that the central government may struggle to promote the common good due to its limited power over the states.