With short selling, you “borrow” a security and sell it at the current price and then buy back the security at a lower price when it’s time to return the securities you borrowed. With puts you’re “buying the right” to sell a security at a set price and you pay a premium to secure that right, but you don’t have to actually do it. So with a short your losses or returns are essentially uncapped but with a put your returns are capped at the price you agreed to minus the premium and your losses are just the premium you paid.
With short selling, you “borrow” a security and sell it at the current price and then buy back the security at a lower price when it’s time to return the securities you borrowed. With puts you’re “buying the right” to sell a security at a set price and you pay a premium to secure that right, but you don’t have to actually do it. So with a short your losses or returns are essentially uncapped but with a put your returns are capped at the price you agreed to minus the premium and your losses are just the premium you paid.