Folly/ˈfɑːli/ Definition 1 of 3Pro Tip 1/3Negative Connotation The word 'folly' often implies a negative judgment or disapproval of the action or belief. Ignoring her advice was pure folly. Pro Tip 2/3Not Always Serious 'Folly' can be used for minor mistakes as well as serious errors in judgment. Missing the meeting due to oversleeping was a small folly. Pro Tip 3/3Subjective Term What one person sees as 'folly' might be considered reasonable by someone else. Some saw her solo travel as folly; others admired it.