What is an auto-antonym?
Wclarke writes, 'The word cleave means both to split apart and to stick to. Are there any other words in English like this?'
These words are called auto-antonyms, they have meanings which are the opposite of themselves. Cleave is a homonym, although it is now one word with two separate meanings, it was originally two words - cleave (separate) from the Old English cleofan and cleave (adhere) from the Old English clifian. Another way auto-antonyms have occurred is through changes in word meaning over the centuries.
Bryson, citing Simeon Potter, writes that James II on seeing St Paul’s Cathedral in London pronounced it ‘amusing, awful and artificial’ meaning ‘pleasing to look at, deserving of awe and full of skillful artifice’, overtime though these original meanings have become obsolete. This has happened with some words that have kept their original meanings in some particular contexts. ‘Let’, for example, used to mean ‘forbid’ and is still used in the legal phrase ‘without let or hindrance’, even though in general use it now means ‘allow’.
Some auto-antonyms include:
Bolt – to secure in place or to dash away
Clip – to fasten together, to cut off.
Sanction – to permit, to restrict
Splice – to join together, to cut in two
There are many more offered here.