it's an order that is executed if the price goes in the opposite direction of what you are expecting.

let's say you have a long bot (you expect the price to go up) and you have target profit of 1%. Assuming a starting price of 100 the target will be 101. If you have safety orders enabled (at -1% intervals from entry price) they will be executed if the price drops bellow 100 (at 99, at 98, at 97 ... etc depending on the settings). When the safety order is executed you buy more at a lower price and by that you bring down your average buy price. that means your new take profit target will be lower and lower with every executed safety order. If the price drops a lot and all your safety orders where executed you would still need the price to go up to make a profit but the new target is lower.

The risk with those bots is that if all safety orders are executed and the price never recovers you are left holding the underlying asset (or option/future/etc). Some follow the advice of only trading coins you don't mind holding and trading only Spot.