that sleeps (cf. a sleeping child), nor is a dancing-hall actually dancing (cf. dancing pairs).
The shift of meaning becomes much more pronounced in the second group of examples.
(2)Blackboard, blackbird, football, lady-killer, pick pocket, good-for-nothing, lazybones, chatterbox.
In these compounds one of the components (or both) has changed its meaning: a blackboard is neither a board nor necessarily black, football is not a ball but a game, a chatterbox not a box but a person, and a lady-killer kills no one but is merely a man who fascinates women. It is clear that in all these compounds the meaning of the whole word cannot be defined as the sum of the constituent meanings. The process of change of meaning in some such words has gone so far that the meaning of one or both constituents is no longer in the least associated with the current meaning of the corresponding free form, and yet the speech community quite calmly accepts such seemingly illogical word groups as a white blackbird, pink bluebells or an entirely confusing statement like: Blackberries are red when they are green.
Yet, despite a certain readjustment in the semantic structure of the word, the meanings of the constituents of the compounds of this second group are still transparent: you can see through them the meaning of the whole complex. Knowing the meanings of the constituents a student of English can get a fairly clear idea of what the whole word means even if he comes across it for the first time. At least, it is clear that a blackbird is some kind of bird and that a good-for-nothing is not meant as a compliment.
(3)In the third group of compounds the process of deducing the meaning of the whole from those of the constituents is impossible. The key to meaning seems to have been irretrievably lost: ladybird is not a bird, but an insect, tallboy not a boy but a piece of furniture,