The opposite of shorting is just buying the stock: exchange the market price $X for a share of stock today, sell later for $Y, profit or loss is $Y - $X. You've made money if the stock has gone UP. Since there's no upper bound on the price of a share but the lower bound is $0, you can lose at most your initial outlay $X, but potential gains are uncapped.
Shorting a stock is borrowing the stock: that is, you get a share of stock today (and sell it today for market price $X) but are liable for returning the share of stock at some time in the future (you obtain it from the market at $Y to do so). The profit or loss is thus $X - $Y. Since there's no upper bound on the price of a share but the lower bound is $0, you can gain at most your initial outlay $X if the price goes to zero, but potential losses are uncapped.
Shorting a stock is borrowing the stock: that is, you get a share of stock today (and sell it today for market price $X) but are liable for returning the share of stock at some time in the future (you obtain it from the market at $Y to do so). The profit or loss is thus $X - $Y. Since there's no upper bound on the price of a share but the lower bound is $0, you can gain at most your initial outlay $X if the price goes to zero, but potential losses are uncapped.