A mental stop is when a computer order is not placed to exit a trade for us, but instead we leave the position open with no offsetting order to control our loss. A
stop order is not placed, but the trader still has a level in mind where he or she will exit a losing position (or a winning position using a trailing mental stop).
A soft stop can also refer to a mental stop that is not at a fixed price. The trader may have a
range of values in mind where he or she will exit based on market conditions.
Source:
https://www.investopedia.com/articles/trading/09/soft-mental-stops.asp
As opposed to a
Hard Stop
See also:
https://www.streetdirectory.com/travel_guide/37583/investment/pros_and_cons_of_mental_stop_and_hard_physical_stops.html
https://www.forex4noobs.com/forex-blog/forex-tips/using-mental-stop-losses/
https://www.mistakesintrading.com/failure-to-control-risk/using-mental-stops-in-trading.php
https://www.swing-trade-stocks.com/stop-loss-orders.html