I’m not disagreeing that it can sometimes happen as you’ve illustrated above. I am saying that it often does happen that coiners of new words know just what they mean by them. The person who came up with ‘electrocute’ knew exactly what he meant by it - to kill with electricity (notice how the word is a portmanteau of electricity and execute). That the word has started to be used by some as a word to mean something less specific is to me unfortunate, but is a good example of how words change over time. At any rate, it seems obvious that sometimes the definitions of words arrive fully formed at their birth, though not always so