Recklessly bold or daring without proper concern for danger or consequences; showing foolish courage.
From 'fool' (a silly or stupid person) plus 'hardy' (bold or brave). The combination suggests the contradiction: bravery without wisdom. Emerged in Middle English as a compound criticizing thoughtless boldness.
The word pairs two contradictory ideas—'hardy' is usually good (being brave), but 'foolhardy' makes it bad by adding 'fool' to it. It's one of English's ways of saying some courage is actually cowardice in disguise.
Complete word intelligence in one call. Free tier — 50 lookups/day.