Overmuch and Over

Overmuch adverb - Beyond a normal or acceptable limit.

Over and overmuch are semantically related in excessive topic. In some cases you can use "Over" instead the word "Overmuch" as an adverb or an adjective, when it comes to topics like unduly.

Over adverb - From one side to the other of an intervening space.

Overmuch and over are semantically related in in addition topic. Sometimes you can use "Overmuch" instead the word "Over" as an adverb or an adjective.