foolishness
n. uncountablen. the quality of being silly or not showing good judgment. It can also mean a stupid act or a lack of wisdom.
n. the quality of lacking good sense or judgement; unwise or imprudent behaviour. Refers to both the abstract state of being unwise and specific instances of silly actions.
His foolishness cost him a lot of money.
The manager regretted the foolishness of ignoring the early warning signs before the project failed.
While some dismissed his risky investment as pure foolishness, others saw it as a calculated gamble that simply failed to account for an unpredictable market shift.
From Middle English folishnesse, follissnesse, equivalent to foolish + -ness.
Often used with the preposition 'of' to describe a specific person's lack of judgement.