Grammar's not usually my jam, but I love a good word study. I thought I knew a lot about words, but I'd never heard about contronyms (which are technically grammar). Thanks to the BBC show QI, now I'm obsessed.
They're words that are their own opposites.
- Bolt: to run away fast and to secure fast
- Dust: the stuff and the what you do to remove
- Puzzle: a conundrum and what you do to solve it
- Sanction: to allow and to prevent
'Contronym' was coined in 1962, the year of my birth, and it's so rare you won't find it in the regular print Merriam-Webster dictionary -- only in the unabridged edition (and online, natch). The M-Ws even did an entire podcast segment on these little gems.
More kinds of words
Let's do a quick review of their cousins:
Antonyms: words of opposite meaning, like big and small. toxic and nontoxic
Homonyms: words that sound alike, but are spelled differently. examples: too, to and two
Related - Homographs (another one I'll leave to the pros):
- words that are spelled the same, but mean different things. lead (the metal), lead (the verb)
- one of two or more words spelled and pronounced alike but different in meaning (such as the noun quail and the verb quail)
Synonyms: there are actually two definitions for this. I'll let our friends at Merriam-Webster explain.
- one of two or more words or expressions of the same language that have the same or nearly the same meaning in some or all senses
- a word or phrase that by association is held to embody something (such as a concept or quality), like a tyrant whose name has become a synonym for oppression
Pro Tip: If you decide to give some of these a try, remember that context is key to avoiding confusion.