Sometimes, just to heighten the confusion, the same word ends up with contradictory meanings. This kind of word is called a contronym. Sanction, for instance, can either signify permission to do something or a measure forbidding it to be done. Cleave can mean to cut in half or stick together. A sanguine person is either hotheaded and bloodthirsty or calm and cheerful. Something that is fast is either stuck firmly or moving quickly. A door that is bolted is secure, but a horse that has bolted has taken off. If you wind up a meeting you finish it; if you wind up a watch, you start it. To ravish means to rape or to enrapture. Quinquennial describes something that lasts for five years or happens only once in five years. Trying one’s best is a good thing, but trying one’s patience is a bad thing. A blunt instrument is dull, a blunt remark is pointed. Occasionally when this happens the dictionary makers give us different spellings to differentiate the two meanings—as with flour and flower, discrete and discreet—but such orthological thoughtfulness is rare.
Bryson, Bill. The Mother Tongue: English and How it Got That Way. HarperCollins, 1990. p. 70–1
