Thanks for the feedback. It's not "short coining", it's "short selling" or just "shorting" - for short.

Short selling is where you borrow an asset and then sell it. People do it when they expect that asset to go down.

So for example, say you saw bitcoin at $20,000. You say, that's definitely the peak. So you borrow 1 bitcoin from your friend. It goes down to $8,000, and you buy 1 bitcoin. Your friend still has his 1 bitcoin, and you have $12,000 more, because you bought the bitcoin for cheaper.

The reason it's so risky is, what if bitcoin kept going up? If it went up to $50,000, you'd be on the hook for $50,000.