MARY ELLEN SYNON, scorned and furious, has called Rupert Pennant-Rea "dumb" for dumping her when she was a journalist and he was Deputy Governor of the Bank of England. Just the sort of word she would use, I thought; but not just because she is a straight talker. She was raised in the States, where they say "dumb" when we English would probably say "stupid". And dumb is much ruder, stupidity being often more like an aberration than a chronic defect of character. ("How stupid of me," you say when you've forgotten someone's name.) In the Regency period stupid could simply mean "boring", or inducing a temporary state of stupor. ("Another stupid party," Jane Austen would tell Cassandra.)
comes straight from the shoulder. But I was wrong in thinking it began as an American usage. The OED thinks it may have meant "unintelligent" before it meant "speechless", at least in several Germanic languages. Old English seems to have been a significant exception. With us in those days it meant only "mute". Our national character (which I had always imagined to be a comparatively recent invention) must have already been forming. Your prototypical Englishman, so tight of lip, so laconic in speech, never made the mistake of assuming that a person who didn't say much had a vacuous mind. That was left to those jabberers on the Continent, who argued that anyone who neglected the gift of speech must be no better than an animal. Carlyle was not being rude about the English when he said they were a dumb people.
Now things have changed and it is unwise to call a man a dummy, particularly if he is bigger than you are. But a dummy was originally either a deaf mute or a man who kept his mouth shut, no bad thing. There's nothing dumb about our Mary Ellen.