Foolish/ˈfuːlɪʃ/ Definition 1 of 3Pro Tip 1/3Negative Judgment Use when someone's action is clearly unwise, showing disapproval. Ignoring her advice was a foolish error. Pro Tip 2/3Consequences Matter Often used when bad judgment leads to negative outcomes. His foolish pride resulted in a lost friendship. Pro Tip 3/3Serious Topics Typically relates to important matters, not trivial ones. A foolish strategy could cost the company greatly.