English is mildly notorious for its non-compositional compounds. In this case I don't necessarily mean that compound words or phrases have nothing to do semantically with their components, but rather that the relation between the components is somewhat unstructured: there is no strict relation between X and Y for a compound X-Y. One relatively well-used example of this is the difference in the semantic relation between the two components in "olive oil" and "baby oil". You make olive oil by squeezing olives until the oil runs out of them. This is not how you make baby oil. In fact, the first word in "baby oil" has a completely different relation than the first word in "olive oil". In "olive oil" the first word indicates the source of the primary component, the oil. (Compounds in English and some other languages are right-headed, meaning that the component on the right gives you the category and basic sense of the compound: "olive oil" is a type of oil, not a type of olive.) In "baby oil", on the other hand, the first word tells you something about how the oil is intended to be used. You can see the same difference in "spring water" and "holy water". Holy water may in fact be spring water (I'm not sure if churches typically use bottled water, tap water, or some specially sourced water for this), but "holy water" indicates something different because it indicates what the water is going to be used for, rather than where it came from.
One thing I hadn't thought much about until recently is that it's not just N+N compounds that behave in this peculiar way. For instance, there's good reason to be afraid of baseball-sized hail, but no real reason to fear a family-sized bag of candy. Like the N+N example above, these types of adjectival compounds can refer to completely different types of relations. Hail that is baseball-sized is the size of a baseball, but a bag of candy that is family-size is not the size of a family; rather, it's a bag that is a size appropriate for a family. English is not the only language that has these types of unpredicatable compounds. Blackfoot also has some unpredictable compounds. One of my favorite of these is the word for horse, ponokáómitaa literally means elk-dog, where ponoka is 'elk' and ómitaa is a bound form of the root for 'dog'. Presumably this stems from the association of horses, when they were first encountered a few hundred years ago, with the general ungulate form and size of an elk, and with the beast-of-burden function of a dog, which the Blackfeet used to carry travois and other equipment.
Jerome Stueart interview (pt. 3)
6 days ago