The comments in an older question of mine on E.S.E leave an issue unresolved: What does one call the situation in which a taboo concept is referred to as being a specific case of a more general nonvulgar concept?
The specific example that I would like to address is the Hebrew verb לדעת. This verb has several meanings. One meaning is to have knowledge of. Another meaning is to have sexual relations with. One could argue that the latter is a what for the former?