A genetic fallacy is a form of irrelevancy in which an idea is endorsed or condemned according to its past merits or demerits rather than its present value. This would not be a genetic fallacy if the idea's history actually affects its present merits.
The meaning of words evolves over time, so that the same word comes to convey a different meaning. The older, typically archaic, word is called an "etymon", and it is from the etymon that the current word is derived.
A semantic etymological fallacy would involve confusing the current meaning of a word with the meaning of one of its etymons. Such a meaning-confusion would devolve into a logical fallacy whenever the premises use the historic meaning yet the conclusion is based on the current rather than historic meaning of the word. To make an argument that confuses ancient and current meanings commits a logical error similar to the fallacy of equivocation (confusing two meanings of the same word). Logical etymological fallacies differs from equivocation in that the etymological fallacy involves the meanings of two different, but etymologically connected words.
This site gives a good description of etymological confusion resulting from too narrow an interpretation of the meaning of the Greek word "logos", from which the modern word logic is derived.