Which term signifies not just abundance, but an excessive amount?

The term that signifies not just abundance, but an excessive amount is "surfeit." This word specifically indicates a point where there is more than what is needed or more than what is healthy. It conveys a sense of overindulgence or an excessive supply, suggesting that the quantity exceeds the desired or optimal level.

In contrast, "profusion" refers to a large quantity but does not inherently convey a sense of excess or overabundance. "Overflow" suggests a spilling over of excess, but again, it doesn't explicitly denote the qualitative aspect of being excessive. "Extravagance" indicates excessive behavior or spending, but it does not directly pertain to a specific quantity or amount in the way that "surfeit" does.

Thus, "surfeit" encapsulates the idea of an excessive amount best among the options presented.